Shérazade Gatfaoui

CONCEPTIONS 1 AND MECHANISMS OF TRUST IN THE CUSTOMER/BANK RELATIONSHIP : A QUALITATIVE AND LONGITUDINAL STUDY

Keywords: interpersonal trust, institutional trust, customer/bank relationship, retrospective case studies. Track : relationship marketing

This paper analyzes the conceptions and the mechanisms of trust, both institutional and interpersonal, in a long term customer/bank relationship. A qualitative and longitudinal study was adopted, based on 18 retrospective case studies conducted within a French bank. Each case focuses on the relationship between a customer and his financial adviser, at the time when the study was carried out. Further, we analyze the conceptions of trust from the two perspectives of the customer and of the financial adviser. The results have important implications for understanding the different meanings and mechanisms of institutional trust and interpersonal trust in the customer/bank relationship.

Introduction

The concept of trust has been studied extensively in various fields, including psychology, sociology, economics, management and marketing. However, the abundance of studies on trust and its transversal character has given rise to a multiplicity of definitions which limits understanding of the concept in the field of commercial relations. The literature to date has tended to view the relationship with the customer from the service provider's perspective. Few studies have used a dyadic approach based on retrospective event histories from the two perspectives of the customer and the financial adviser to examine various conceptions of trust. Following [START_REF] Brown | A Gap Analysis of Professional Service Quality[END_REF], we have considered the perceptions of both parties in the customer/bank relationship and have compared them. By means of qualitative in-depth interviews with customers and financial advisers, the study analyses retrospective event histories to gain a clearer understanding of the concept of trust. Drawing on the literature, the first part of the paper focuses on the difficulty in conceptualizing trust by examining definitions of trust in various disciplines. This is followed by a discussion of the research methodology based on a qualitative and longitudinal study conducted in a French bank. Finally the results of the study are presented and interpreted, along with a discussion of its conclusions.

The concept of trust in the literature

The notion of trust has been gradually introduced into studies in psychology, sociology, economics and, most recently, management and marketing. Depending the context in which it is applied, trust can be variously defined as a belief, an expectation, a feeling, a behavioral intention or a willingness to rely on an exchange partner (Moorman, Zaltman and Deshpande, 1992). Certain authors consider that trust is made up either of two componentscredibility and benevolence [START_REF] Doney | An examination of the nature of trust in buyer-seller relationships[END_REF][START_REF] Ganesan | Determinants of long-term orientation in buyer-seller relationship[END_REF][START_REF] Morgan | The commitment-trust Theory of Relationship Marketing[END_REF])or of threecredibility, honesty and benevolence [START_REF] Hess | Construction and assessment of a scale to measure consumer trust, Conference AMA Educators[END_REF]. The definitions expounded do not explicitly include the question of the dynamic of trust, its development according to the history or shared experience of the partners, or to any incidents encountered during the customer/bank relationship. This account seems consistent in so far as the studies have often aimed at defining and measuring trust at a given moment (t) by means of measurement scales while ignoring the consumer's perception in a qualitative and longitudinal perspective. Facing the growing number of conceptions and definitions of trust, certain authors have also wondered whether trust should be viewed as interpersonal, based on individuals knowing one another, rather than as institutional, based on the reputation of the firm or institution (Williamson, 1993 ;[START_REF] Young | The role of trust and co-operation in marketing channels : a preliminary study[END_REF]. If different kinds of trust exist in a commercial relationship -institutional as opposed to interpersonal trust -what are the meanings they are given during such a relationship ?. Little by way of empirical research has been done in this area, although such research would enable the concept and its mechanisms of construction during the relationship to be better understood.

Research methodology

A qualitative and longitudinal study was adopted, based on 18 retrospective case studies conducted within a French bank. Each case focuses on the relationship between a customer and his financial adviser, at the time when the study was carried out. The critical incident method enables us to trace back the historical relationship between a customer and his adviser (Bitner, Booms and Treteault, 1990 ;[START_REF] Flanagan | The critical incident technique[END_REF][START_REF] Keaveney | Customer switching behavior in service industries : an exploratory study[END_REF]. Further, identifying the incidents that come up between a bank and its customers as well as the way they are handled allow us to understand more clearly the meanings of trust and the mechanisms by which it is built. Finally, the dyadic approach allows us to trace back the historical relationship as perceived by the customer and his financial adviser [START_REF] Brown | A Gap Analysis of Professional Service Quality[END_REF][START_REF] Chandon | Service Encounter Dimensions -A Dyadic Perspective : Measuring the Dimensions of Service Encounter as Perceived by Customers and Personnel[END_REF][START_REF] Deshpandé | Corporate Culture, Customer Orientation, and Innovativeness in Japanes Firms : A Quadrad Analysis[END_REF]. The retrospective interviews were set up one to one and they allow us to trace back the customer's bank history based on the relationship between a customer and his financial adviser). The interviews were set up in five different branches of the bank in three departments in Paris (Paris-Ouest = 2 branches, Paris-Est = 2 branches and Paris Hauts-de-Seine = 1 branch). Customers were selected by the financial advisers at the various branches, on the basis of our instructions. Clarifying conceptions of trust in the private customer/bank relationship necessarily involved choosing those customers having a reasonably substantial bank product and services portfolio. Customers needed to have sufficient experience of bank services to be able to discuss trust, and to have been in the adviser's customer portfolio for more than a year. In addition, the customers selected were required to have maintained regular contact with their existing adviser. Financial advisers were also required to have dealt at least once with both negative events (either incidents in the customer's private life or critical incidents provoked by the bank) and positive events in the course of their relation with the customer. The incidents in the customer's private life are linked to the customer's personal life and have given rise to problems at the level of his financial situation and of the relationship between the customer and the bank (for example : a period of unemployment, a divorce, a death). The critical incidents provoked by the bank are linked to an error involving the transfer of funds to another customer's account, to the "forced" sale of a financial product or service, or to a refusal to a request for a loan. During the interviews, we asked nine customers aged from 28 to 45 years old and nine customers aged from 55 to 77 years old, and their finacial advisors aged from 23 to 54 years old. Customers aged from 28 to 45 years old are part of the active customers segment and those aged from 55 to 77 years old are part of the senior customers segment, as defined by the bank's classification scheme. The customer's sample was not defined in advance. We have chosen the customers as and when we collected and analyzed the data. Finally, the interviews were recorded, transcribed, then analyzed.

Interpretation and discussion of the case studies

Intra-case and inter-case analyses have pointed out two periods considered as important for understanding conceptions of institutional and interpersonal trust during the customer/bank relationship. The first Period 1, corresponds to the context that preceeded and followed the time at which a customer established a contact with the bank. This context refers to the reasons for and conditions under which a customer establishes contact with the bank. The second Period 2, covers the development of the relationship with the bank. It refers to the history of the customer/financial adviser relationship, irrespective of whether or not this involved a critical incident in this relationship.

Meanings of institutional trust during the customer/bank relationship (period 1 and period 2)

Institutional trust is linked to the notion of credibility of the bank (during the period 1) : During the period 1 which corresponds to the context that preceeded and followed the time at which a customer established a contact with the bank, institutional trust is linked to the notion of credibility of the bank. To account for their decision to enter into a relationship with the bank, customers refer especially to a "degree of trust" in the banking institution concerned. Customers state that their trust in the bank is based on its "size", "reputation" or "expertise" and to the bank's "recognized experience" (Anderson and [START_REF] Weitz | Determinants of continuity in conventional industrial channel dyads[END_REF][START_REF] Doney | An examination of the nature of trust in buyer-seller relationships[END_REF][START_REF] Ganesan | Determinants of long-term orientation in buyer-seller relationship[END_REF]Moorman, Deshpande and Zaltman, 1993;[START_REF] Ring | Structuring cooperative relationships between organizations[END_REF]. These conclusions seem reasonable enough given that, at this point, customers had not yet established a relationship with the bank's financial advisers. Thus, if it is a matter of institutional trust, it would be considered by the customer and would derive from a cognitive process (knowledge of the bank through the press, word of mouth). Hence trust would be defined as a belief on the customer's part based essentially on the cognitive dimension corresponding to the credibility of the bank. Such credibility would be itself explained by the reputation, size, experience or expertise of the bank. The bank's credibility is based on its capacity to offer services that are "more buoyant, more competitive" or "more suited to certain customer profiles" and on "guarantees" and "security" that money invested "won't vanish into thin air". These results refer to all customers who established relationship with the new bank following an incident, whether caused by the former bank (5 customers out of 18 in total) or caused by the customers (6 customers out of 18) and not dealt with or badly handled by the former bank (11 customers in all).

Institutional trust remains linked to the notion of credibility of the bank (during the period 2) :

In the course of the relationship with the financial adviser (period 2), institutional trust remains linked to the notion of the "credibility" of the bank. It remains based on the size, reputation and expertise of the bank, as well as on the customer's experience with the bank's advisors judged as positive or negative overall by customers. In general, these customers emphasize that "the development of relationship with financial advisers, and the way in which they look after their customers' interests when dealing with the bank hierarchy, vindicates and possibly facilitates agreement by the credit department to a request for a loanin a word, how they behave."

Meanings of interpersonal trust during the customer/bank relationship (period 1 and period 2) Interpersonal trust, an expectation in a situation of vulnerability (During the period of entry into relationship with the bank / Period 1)

For customers establishing a relationship with the bank following poor management of incidents by the former bank (mainly incidents provoked by the customer), interpersonal trust is expressed as a mutual expectation (7 customers out of 18). In this context, the relationship is somewhat asymmetrical in favor of the bank. This expectation applies to the mutual trust between the customer and the financial adviser. It occurs in a situation of vulnerability and dependence on the part of the customer in relation to the other party (the bank), and arises for customers prior to the establishing of a relationship with the financial advisers. Thus, they hope "to find a bank where the financial advisers will be capable of trust other than on the basis simply of rational calculation; and to meet financial advisers who they can rely on in the context of financial difficulties."

The financial adviser's trust in the customer should not be based solely on the customer's financial situation (income and financial assets). Indeed, the financial adviser can agree to a loan for the customer simply because he has a number of savings accounts with the bank or a substantial income. In this situation, these various savings accounts represent a financial guarantee for the bank (example 1). If the customer does not necessarily have any financial assets or a large income, or if he encounters financial difficulties, the financial adviser should also taken into account the willingness of the customer to keep his word and to make the necessary arrangements to repay a loan (example 2). In such circumstances, the financial adviser does not trust the customer on the basis of his financial situation but in relation to a willingness to respect his commitments. The customer must then convince his adviser that he will make the necessary effort to repay the loan. The financial adviser, in the course of the meeting, assesses or perceives the willingness of the customer to keep his promises. This perception depends on "intangible" or "incalculable" elements, namely feelings, intuition. In the customer's opinion, this incalculable aspect of trust can exist only in relation to an individual (the adviser) and not to an institution (the bank).

Interpersonal trust, an evolving conception (During the development of the relationship with the bank / Period 2).

For the financial advisers, even if there is a greater or lesser degree of trust on the part of the adviser toward the customer, this is reciprocal but not symmetrical. For financial advisers, the question of interpersonal trust arises basically with reference to a situation deemed risky for the bank. Once they decide that customers are "financially sound" or "profitable in terms of income or savings", the question of trust no longer applies. Thus the customer feels the need more to trust his adviser than the reverse situation, which occurs less frequently. However, this does not mean that advisers never need to trust their customers. Indeed, they recognize this need if the customer represents a greater or lesser financial risk for the bank (for example : following a period of unemployment, a "very good customers who had a monthly salary of around 7000 euro needs to repay a number of outstanding loans"). In this situation, the financial adviser needs to consider the best solutions for the bank and the customer. He has to trust his customer, who will have to adapt his way of life and reduce expenditure during this period. Indeed the risk of exceeding overdraft limits can be very high, as can that of the customer not being able to make monthly repayments. In cases where this question arises, interpersonal trust can take the same forms and courses of development as it does for customers. For both "active" and "senior" customer segments, we find the main definitions of interpersonal trust as suggested in the literature. As in Period 1, trust from the standpoint of the customer can be understood as "an expectation" when he considers himself to be in a situation of dependence in relation to his partners (for example : advisers and the bank in general, through the credit department). This expectation of trust given by the adviser to the customer occurs therefore in a situation of customer vulnerability (following an incident caused by the customer and prior to being managed by the adviser). It can also be experienced as a "feeling", "intuition" or "emotion" according to which the customer can count on the adviser or can invest trust in him and vice versa. This feeling is comparable to the psychological state of the actors (customers and advisers). Interpersonal trust can also be linked to a "belief" or a "willingness on the part of the actors", leading to an "behavioral intention".

Trust as feeling is found :

-either at the beginning of the relationship between the customer and the new financial adviser, when they do not know each other very well, during the entry stage of the relationship with the bank or in the event of repeated changes of adviser, -or prior to an expectation of or a request for a provision of services when they already know each other. According to whether the feeling of trust is put to the test of the actors' behavior, in the event of an incident or independently of an incident, it can be changed into a latent belief or a confirmed belief or into a willingness then an behavioral intention. The change from feeling to belief or willingness and/or behavioral intention is not systematic. It depends on the past experience of the customer and adviser. Before an expectation of or a request for a provision of services, in the event of a critical incident or independently of such an incident, trust can be expressed as a feeling or latent belief, based on previous positive experience by the actors. During or after the administration and implementation of the service provision, trust is expressed as a confirmed belief and/or willingness and/or behavioral intention. The change from one stage to the next thus depends on the involvement and behavior of the actors (customer or adviser) in relation to the customer's or adviser's request or expectation (for example : on the part of the customer, a request for a mortgage loan; or on the part of the adviser, an expectation that a check will be forthcoming from the customer to pay off a substantial overdraft).

Conclusions

The study of trust within a qualitative and longitudinal perspective throws light on "the why" of the different possible meanings of the concept. Thus, once the researcher is clearly positioned in relation to certain elements, we understand more easily why trust can be the bearer of several meanings. Such meanings then depend on : -the type of trust studied (institutional as opposed to interpersonal), -the business sector concerned (consumer goods as opposed to banking services for private individuals), -the context of experiencing services (involving an incident or independently of any incident, as well as a situation of vulnerability on the part of the customer (in the case of an incident caused voluntarily or involuntarily by the customer), the involvement and behavior of the actors (customers and advisers) in the management of their relationship in the event of an incident or independently of any incident, the stage2 of development of the relationship (Period 1 linked to entry into relationship with the bank, Period 2 linked to the development of the relationship with the bank) -and to temporal aspect of the implementation of the services (before, during and after effective implementation).

By conceptions of trust, we understand the types of trust adopted by the customer as well as the meaning or significance given to each type of trust during the customer/bank relationship (from the time of entry into the relationship with the bank until the present). By mechanisms of trust, we understand the factors or the elements which throw light on "the why" of the different possible meanings of trust, both institutional and interpersonal.

The notion of stage refers to the two periods of the relationship as identified by customers an financial advisers -Periods 1 and 2.


Shérazade Gatfaoui

CONCEPTIONS AND MECHANISMS OF TRUST IN THE CUSTOMER/BANK RELATIONSHIP : A QUALITATIVE AND LONGITUDINAL STUDY

Keywords: Services marketing, Customer relationship, Interpersonal trust, Institutional trust, Qualitative and Longitudinal Study, France Services marketing, Customer relationship, Interpersonal trust, Institutional trust, Qualitative and Longitudinal Study, France

This paper analyzes the conceptions and the mechanisms of trust, both institutional and interpersonal, in a long term customer/bank relationship. A qualitative and longitudinal study was adopted, based on 18 retrospective case studies conducted within a French bank. Each case focuses on the relationship between a customer and his financial adviser, at the time when the study was carried out. Further, we analyze the conceptions of trust from the two perspectives of the customer and of the financial adviser. The results have important implications for understanding the different meanings and mechanisms of institutional trust ("credibility") and interpersonal trust ("true trust") in the customer/bank relationship.

Introduction

The concept of trust has been studied extensively in various fields, including psychology, sociology, economics, management and marketing. However, the abundance of studies on trust and its transversal character has given rise to a multiplicity of definitions which limits understanding of the concept in the field of commercial relations. The lack of consensus among researchers as to the meaning of trust is evident in its being defined variously as expectation, belief, feeling or behavioral intention (Moorman, Zaltman and Deshpande, 1992).

French banks are currently facing the challenge both of improving performance in an increasingly competitive banking environment, and of creating and building up a genuine relationship based on trust with customers. Since trust is a key concept in understanding the buyer-seller relationships, this paper focuses on the conceptions and the mechanisms of trust, both institutional (credibility) and interpersonal ("true" trust), in a long-term customer/bank relationship. By conceptions of trust, we understand the types of trust adopted by the customer as well as the meaning or significance given to each type of trust during the customer/bank relationship (from the time of entry into the relationship with the bank until the present). By mechanisms of trust, we understand the factors or the elements which throw light on "the why" of the different possible meanings of trust, both institutional (credibility) and interpersonal (true trust).

The literature to date has tended to view the relationship with the customer from the service provider's perspective. Few studies have used a dyadic approach based on retrospective event histories from the two perspectives of the customer and the financial adviser to examine various conceptions of trust. Following [START_REF] Brown | A Gap Analysis of Professional Service Quality[END_REF], we have considered the perceptions of both parties in the customer/bank relationship and have compared them. By means of qualitative in-depth interviews with customers and financial advisers, the study analyses retrospective event histories to gain a clearer understanding of the concept of trust.

Drawing on the literature, the first part of the paper focuses on the difficulty in conceptualizing trust by examining definitions of trust in various disciplines. This is followed by a discussion of the research methodology based on a qualitative and longitudinal study conducted in a French bank. Finally the results of the study are presented and interpreted, along with a discussion of its conclusions.

The concept of trust in the literature

The notion of trust has been gradually introduced into studies in psychology, sociology, economics and, most recently, management and marketing. In a special issue of the journal Academy of Management Review, a number of authors point to the varying approaches to trust taken in different disciplines [START_REF] Rousseau | Not so different after all : A cross discipline view of trust[END_REF]. According to these authors, psychologists assimilate trust to the personality and to the individual's behavior patterns [START_REF] Deutsch | Trust and suspicion[END_REF][START_REF] Deutsch | The effect of motivation orientation upon trust and suspicion[END_REF]Larzerel and Huston, 1980). Some economists are opposed to making use of the notion of trust to explain economic exchanges [START_REF] Williamson | Calculativeness, trust and economic organization[END_REF]. Also, the use of the term trust is not suited to describing commercial transactions in which the guarantees of costs and benefits have been foreseen in order to improve the overall effectiveness of the transaction. Finally, sociologists maintain that trust is embedded in the economic and social spheres [START_REF] Gambetta | Can we trust trust[END_REF][START_REF] Granovetter | Economic action an social structure : the problem of embeddedness[END_REF]. From this perspective, trust is not a phenomenon based exclusively on calculation, but is established and constructed within the framework of social relationships. As a result, it takes account of the personalities of the individuals involved in the relationship, and of their feelings and past experience, as in all social relationships existing between two individuals. Trust is also an institutional phenomenon because it is based on institutions [START_REF] Barder | The service encounter : diagnosing favorable and unfavorable incidents[END_REF][START_REF] Zucker | Production of trust : institutional sources of economic structure[END_REF].

Depending the context in which it is applied, trust can be variously defined as a belief, an expectation, a feeling, a behavioral intention or a willingness to rely on an exchange partner. Certain authors consider that trust is made up either of two componentscredibility and benevolence [START_REF] Doney | An examination of the nature of trust in buyer-seller relationships[END_REF][START_REF] Ganesan | Determinants of long-term orientation in buyer-seller relationship[END_REF][START_REF] Morgan | The commitment-trust Theory of Relationship Marketing[END_REF] or of three credibility, honesty and benevolence [START_REF] Hess | Construction and assessment of a scale to measure consumer trust[END_REF]. The definitions expounded do not explicitly include the question of the dynamic of trust, its development according to the history or shared experience of the partners, or to any incidents encountered during the customer/bank relationship. This account seems consistent in so far as the studies have often aimed at defining and measuring trust at a given moment (t) by means of measurement scales while ignoring the consumer's perception in a qualitative and longitudinal perspective. Facing the growing number of conceptions and definitions of trust, certain authors have also wondered whether trust should be viewed as interpersonal, based on individuals knowing one another, rather than as institutional, based on the reputation of the firm or institution [START_REF] Williamson | Calculativeness, trust and economic organization[END_REF][START_REF] Young | The role of trust and co-operation in marketing channels : a preliminary study[END_REF].

While there is no general consensus on the definition of trust, its status in management is clear. Trust contributes to the success and stability of exchanges. It reduces uncertainty, exchange-related costs and inequalities, and results in advantages in the long term. Trust also favors tolerance and concessions being made by the individuals concerned. If different kinds of trust exist in a commercial relationship -institutional as opposed to interpersonal trustwhat are the meanings they are given during such a relationship ?. Little by way of empirical research has been done in this area, although such research would enable the concept and its mechanisms of construction during the relationship to be better understood. This line of inquiry is all the more interesting since it concerns the banking services sector characterized by a high level of percieved risk depending on the intangibility, simultaneity of production and consumption, and variability of services.

Research methodology

A qualitative and longitudinal study was adopted, based on 18 retrospective case studies conducted within a French bank. Each case focuses on the relationship between a customer and his financial adviser, at the time when the study was carried out. From a general point of view, the case-study method ensures that dynamic phenomena are understood [START_REF] Yin | Case study research, design and methods[END_REF]. Moreover, the critical incident method enables us to trace back the historical relationship between a customer and his adviser (Bitner, Booms and Treteault, 1990 ;[START_REF] Flanagan | The critical incident technique[END_REF][START_REF] Keaveney | Customer switching behavior in service industries : an exploratory study[END_REF]. Further, identifying the incidents that come up between a bank and its customers as well as the way they are handled allow us to understand more clearly the meanings of trust and the mechanisms by which it is built. Finally, the dyadic approach allows us to trace back the historical relationship as perceived by the customer and his financial adviser [START_REF] Brown | A Gap Analysis of Professional Service Quality[END_REF][START_REF] Chandon | Service Encounter Dimensions -A Dyadic Perspective : Measuring the Dimensions of Service Encounter as Perceived by Customers and Personnel[END_REF][START_REF] Deshpandé | Corporate Culture, Customer Orientation, and Innovativeness in Japanes Firms : A Quadrad Analysis[END_REF].

The retrospective interviews were set up one to one and they allow us to trace back the customer's bank history based on the relationship between a customer and his financial adviser). The interviews were set up in five different branches of the bank in three departments in Paris (Paris-Ouest = 2 branches, Paris-Est = 2 branches and Paris Hauts-de-Seine = 1 branch). Customers were selected by the financial advisers at the various branches, on the basis of our instructions. Clarifying conceptions of trust in the private customer/bank relationship necessarily involved choosing those customers having a reasonably substantial bank product and services portfolio. Customers needed to have sufficient experience of bank services to be able to discuss trust, and to have been in the adviser's customer portfolio for more than a year. In addition, the customers selected were required to have maintained regular contact with their existing adviser. Financial advisers were also required to have dealt at least once with both negative events (either incidents in the customer's private life or critical incidents provoked by the bank) and positive events in the course of their relation with the customer. The incidents in the customer's private life are linked to the customer's personal life and have given rise to problems at the level of his financial situation and of the relationship between the customer and the bank (for example : a period of unemployment, a divorce, a death). The critical incidents provoked by the bank are linked to an error involving the transfer of funds to another customer's account, to the "forced" sale of a financial product or service, or to a refusal to a request for a loan.

During the interviews, we asked nine customers aged from 28 to 45 years old and nine customers aged from 55 to 77 years old, and their finacial advisors aged from 23 to 54 years old. Customers aged from 28 to 45 years old are part of the active customers segment and those aged from 55 to 77 years old are part of the senior customers segment, as defined by the bank's classification scheme. The customer's sample was not defined in advance. We have chosen the customers as and when we collected and analyzed the data. Finally, the interviews were recorded, transcribed, then analyzed.

Interpretation and discussion of the case studies

Intra-case and inter-case analyses have pointed out two periods considered as important for understanding conceptions of institutional and interpersonal trust during the customer/bank relationship. The first Period 1, corresponds to the context that preceeded and followed the time at which a customer established a contact with the bank. This context refers to the reasons for and conditions under which a customer establishes contact with the bank. The second Period 2, covers the development of the relationship with the bank. It refers to the history of the customer/financial adviser relationship, irrespective of whether or not this involved a critical incident in this relationship.

Meanings of institutional trust during the customer/bank relationship (period 1 and period 2) Institutional trust is linked to the notion of credibility of the bank (during the period 1) :

During the period 1 which corresponds to the context that preceeded and followed the time at which a customer established a contact with the bank, institutional trust is linked to the notion of credibility of the bank. To account for their decision to enter into a relationship with the bank, customers refer especially to a "degree of trust" in the banking institution concerned. Customers state that their trust in the bank is based on its "size", "reputation" or "expertise" and to the bank's "recognized experience" (Anderson and [START_REF] Weitz | Determinants of continuity in conventional industrial channel dyads[END_REF][START_REF] Doney | An examination of the nature of trust in buyer-seller relationships[END_REF][START_REF] Ganesan | Determinants of long-term orientation in buyer-seller relationship[END_REF]Moorman, Deshpande and Zaltman, 1993;[START_REF] Ring | Structuring cooperative relationships between organizations[END_REF]. These conclusions seem reasonable enough given that, at this point, customers had not yet established a relationship with the bank's financial advisers.

While its seems consistent to find this type of trust in what customers say, it is rather the meaning given to the concept which is interesting. The various analyses of conceptions of trust led us to inquire as to the pertinence of the concept of institutional trust which allies itself more with the notion of the "credibility" of the bank. Thus, if it is a matter of institutional trust, it would be considered by the customer and would derive from a cognitive process (knowledge of the bank through the press, word of mouth). Hence trust would be defined as a belief on the customer's part based essentially on the cognitive dimension corresponding to the credibility of the bank. Such credibility would be itself explained by the reputation, size, experience or expertise of the bank. However, and in so far as customers accept the bank's credibility based on its capacity to offer services that are "more buoyant, more competitive" or "more suited to certain customer profiles" and on "guarantees" and "security" that money invested "won't vanish into thin air", for the customers it is difficult to speak of "true trust" in the bank.

Indeed, those customers who entered into a relationship with the bank following bad management of incidents by their former bank asked the following question (11 customers out in a total of 18 cases) : "When the bank is incapable of returning the trust the customer has given it, is it possible to speak of a genuine relationship of trust?". These results refer to all customers who established relationship with the new bank following an incident, whether caused by the former bank (5 customers out of 18 in total) or caused by the customers (6 customers out of 18) and not dealt with or badly handled by the former bank (11 customers in all).

This reflection is all the more justified in that it involves a situation of vulnerability for the customer, especially for the customers who left their former bank following incidents badly handled by the bank concerned. For example, in the event of financial difficulties experienced by the customer, the relationship can be summed up in terms of "guarantees" or "risks" for the bank. In such cases, the financial adviser's trust in the customer goes no further than the idea of financial credibility defined as "financial guarantees, income or savings". The bank is comparable to an opportunist company interested in "customers so long as they've got money". For such customers, the existence of "true trust" going beyond the financial guarantees provided by the customer is possible only in the relationship "between individuals who have experience in common, learn from each other and mutually respect each other". In the customer's point of view, what the bank has to say about trust is nothing other than "packaging or an advertising image to attract customers".

Conceptions and mechanisms of institutional trust during the period 1 are provided below (figure 1). In the figure, the order of the factors mentioned is unrelated to their relative importance. The figure aims basically to show the main factors used by customers, enabling the idea of institutional trust linked to the bank's credibility to be understood and explained -Period 1).

Figure 1. Conceptions and mechanisms of institutional trust (credibility) -(period 1)

Institutional trust remains linked to the notion of credibility of the bank (during the period 2) :

In the course of the relationship with the financial adviser (period 2), institutional trust remains linked to the notion of the "credibility" of the bank. It remains based on the size, reputation and expertise of the bank, as well as on the customer's experience with the bank's advisors judged as positive overall by customers. In general, these customers emphasize that "the development of relationship with financial advisers, and the way in which they look after their customers' interests when dealing with the bank hierarchy, vindicates and possibly facilitates agreement by the credit department to a request for a loanin a word, how they behave." It therefore seems difficult to conclude that there exists "genuine" institutional trust going beyond the "financial credibility" of the customer.

Conceptions and mechanisms of institutional trust during the period 2 are provided below in (figure 2). In the figure, the order of the factors mentioned is unrelated to their relative importance. The figure aims basically to show the main factors used by customers, enabling the idea of institutional trust linked to the bank's credibility to be understood and explained.

Reputation (Contexts 1 and 2)

Based on the capacity of the bank to offer services that are "more competitive" or "more suited to certain customer profiles" and "on guarantees" and "security" that money invested "won't vanish into thin air".

Expertise (contexts 1 and 2)

Based on the bank's "recognized experience"

Size (contexts 1 and 2)

Customers emphasize the nationwide geographical presence of the bank -its size is perceived as an indicator of the bank's financial standing.

Institutional Trust (contexts 1 and 2)

As the "Credibility of the bank"

Contexts in which costumers entered into a relationship with the bank

Context 1 -Customers who entered into a relationship with the bank not as a result of bad management of critical incidents by their former bank -(the customer opened his first bank account at this bank) -Based on previous positive experience by the customer and the adviser at this bank.

Context 2 -Customers who entered into a relationship with the new bank following bad management of critical incidents by their former bank (incidents provoked by the former bank and/or caused by the customers) -Based on negative experience by the customer and the advisers at the former bank -"True trust" can exist only in relation to an individual (the adviser) and not to an institution (the bank) -The former bank is comparable to an opportunist company.

Figure 2. Conceptions and mechanisms of institutional trust (credibility) -(period 2)

Meanings of interpersonal trust during the customer/bank relationship (period 1 and period 2)

Interpersonal trust, an expectation in a situation of vulnerability (During the period of entry into relationship with the bank / Period 1) For customers establishing a relationship with the bank following poor management of incidents by the former bank (mainly incidents provoked by the customer), interpersonal trust is expressed as a mutual expectation (7 customers out of 18). In this context, the relationship is somewhat asymmetrical in favor of the bank. This expectation applies to the mutual trust between the customer and the financial adviser. It occurs in a situation of vulnerability and dependence on the part of the customer in relation to the other party (the bank), and arises for customers prior to the establishing of a relationship with the financial advisers. Thus, they hope "to find a bank where the financial advisers will be capable of trust other than on the basis simply of rational calculation; and to meet financial advisers who they can rely on in the context of financial difficulties."

The financial adviser's trust in the customer should not be based solely on the customer's financial situation (income and financial assets). Indeed, the financial adviser can agree to a loan for the customer simply because he has a number of savings accounts with the bank or a substantial income. In this situation, these various savings accounts represent a financial guarantee for the bank (example 1).

If the customer does not necessarily have any financial assets or a large income, or if he encounters financial difficulties, the financial adviser should also taken into account the willingness of the customer to keep his word and to make the necessary arrangements to repay a loan (example 2). In such circumstances, the financial adviser does not trust the customer on the basis of his financial situation but in relation to a willingness to respect his commitments. The customer must then convince his adviser that he will make the necessary effort to repay

Reputation (Contexts 1 and 2)

Based on the capacity of the bank to offer services that are "more competitive" or "more suited to certain customer profiles" and "on guarantees" and "security" that money invested "won't vanish into thin air"

Expertise (contexts 1 and 2)

Based on the bank's "recognized experience"

Size (contexts 1 and 2)

Customers emphasize the nationwide geographical presence of the bank -its size is perceived as an indicator of the bank's financial standing.

Institutional Trust (contexts 1 and 2)

As the "Credibility of the bank"

Experience of past services (involving an incident caused by the bank or customers, or independently of any incident)

Satisfaction (based on previous positive experience by the customer and the advisers at the bank) The customer's experience with the bank's advisers (judged as positive or negative overall by customers)

Lack of satisfaction (based on previous negative experience by the customer and the advisers of the bank) the loan. The financial adviser, in the course of the meeting, assesses or perceives the willingness of the customer to keep his promises. This perception depends on "intangible" or "incalculable" elements, namely feelings, intuition. In the customer's opinion, this incalculable aspect of trust can exist only in relation to an individual (the adviser) and not to an institution (the bank). Conception and mechanisms of interpersonal trust during the period 1 are provided below (figure 3). In the figure, the order of the factors mentioned is unrelated to their relative importance. The figure aims basically to show the main factors used by customers, enabling the idea of interpersonal trust linked to the notion of "true" trust to be understood and explained. For the financial advisers, even if there is a greater or lesser degree of trust on the part of the adviser toward the customer, this is reciprocal but not symmetrical. For financial advisers, the question of interpersonal trust arises basically with reference to a situation deemed risky for the bank. Once they decide that customers are "financially sound" or "profitable in terms of income or savings", the question of trust no longer applies. Thus the customer feels the need more to trust his adviser than the reverse situation, which occurs less frequently. However, this does not mean that advisers never need to trust their customers. Indeed, they recognize this need if the customer represents a greater or lesser financial risk for the bank (for example : following a period of unemployment, a "very good customers who had a monthly salary of around 7000 euro needs to repay a number of outstanding loans"). In this situation, the financial adviser needs to consider the best solutions for the bank and the customer. He has to trust his customer, who will have to adapt his way of life and reduce expenditure during this period. Indeed the risk of exceeding overdraft limits can be very high, as can that of the customer not being able to make monthly repayments. In cases where this question arises, interpersonal trust can take the same forms and courses of development as it does for customers.

For both "active" and "senior" customer segments, we find the main definitions of interpersonal trust as suggested in the literature. As in Period 1, trust from the standpoint of the customer can be understood as "an expectation" when he considers himself to be in a situation of dependence in relation to his partners (for example : advisers and the bank in general, through the credit department). This expectation of trust given by the adviser to the customer occurs therefore in a situation of customer vulnerability (following an incident caused by the customer and prior to being managed by the adviser). It can also be experienced as a "feeling", "intuition" or "emotion" according to which the customer can count on the

The context in which customers entered into a relationship with the bank (context 2)

Customers who entered into a relationship with the new bank following bad management of critical incidents by their former bank (incidents provoked by the former bank and/or caused by the customers) -"True trust" can exist only in relation to an individual (the adviser) and not to an institution (the bank)

Interpersonal trust

As "True trust"

And

As a "mutual expectation" (between the customer and the adviser) adviser or can invest trust in him and vice versa. This feeling is comparable to the psychological state of the actors (customers and advisers). Interpersonal trust can also be linked to a "belief" or a "willingness on the part of the actors", leading to an "behavioral intention".

Trust as feeling is found : -either at the beginning of the relationship between the customer and the new financial adviser, when they do not know each other very well, during the entry stage of the relationship with the bank or in the event of repeated changes of adviser, -or prior to an expectation of or a request for a provision of services when they already know each other. According to whether the feeling of trust is put to the test of the actors' behavior, in the event of an incident or independently of an incident, it can be changed into a latent belief or a confirmed belief or into a willingness then an behavioral intention.

The change from feeling to belief or willingness and/or behavioral intention is not systematic. It depends on the past experience of the customer and adviser. Before an expectation of or a request for a provision of services, in the event of a critical incident or independently of such an incident, trust can be expressed as a feeling or latent belief, based on previous positive experience by the actors. During or after the administration and implementation of the service provision, trust is expressed as a confirmed belief and/or willingness and/or behavioral intention. The change from one stage to the next thus depends on the involvement and behavior of the actors (customer or adviser) in relation to the customer's or adviser's request or expectation (for example : on the part of the customer, a request for a mortgage loan; or on the part of the adviser, an expectation that a check will be forthcoming from the customer to pay off a substantial overdraft).

Conversely, notions of willingness and feeling can sometimes occur irrespective of the situation of the customer whether vulnerable or not, and the temporal aspect of the provision of services. Indeed it has not been possible to classify trust defined as a willingness to rely on his partner, according to the specific situation of the customer (vulnerability or not) and according to the temporal aspect of provision of services (before, or rather during and after, the effective implementation of the services). On the basis of what customers in particular assert, this conception could occur independently of these two criteria. This considered willingness is expressed within a more general perspective. It can be linked to past experience deemed to be positive overall. It seems also to be justified by a lack of expertise on the customer's part or to a predisposition to trust based on an individual characteristic of the customer. Furthermore, according to what both customers and advisers report, trust in an overall sense can sometimes be considered as a "feeling, something intangible" independently of the situation and the temporal aspect of the implementation of service provision. Approached within a global perspective, trust could be considered as a feeling, an intuition. For example, in answer to the question "What does trust mean to you at this very moment?", customers variously replied : "It's a sensation…, a feeling that can't be explained…, something intangible… either you feel it or you don't…". On the other hand, it is more with reference to experience of past services that trust also becomes apparent as a feeling before the implementation of the services or when the customer and adviser do not know each other, during the entry stage of the customer's relation with the bank or when advisers are continually replaced.

Meanings and mechanims of interpersonal trust during the development of the customer/bank relationship (period 2) are provided in the figure 4.

Conclusions, limitations and directions for future research

The main marketing studies have enabled trust to be "photographed", i.e. measured at a given time (t). Depending on the stage of development of the relationship 1 , depending on the situation the customer is in (pertaining to an incident or independently of any incident), and depending on whether or not to trust has been put to the test of the actors' behavior in the course of experiencing services, it can be expressed as a feeling, a belief, a willingness or a behavioral intention.

The study of trust within a qualitative and longitudinal perspective throws light on "the why" of the different possible meanings of the concept. Thus, once the researcher is clearly positioned in relation to certain elements, we understand more easily why trust can be the bearer of several meanings. Such meanings then depend on:

-the type of trust studied (institutional as opposed to interpersonal), -the business sector concerned (consumer goods as opposed to banking services for private individuals), -the context of experiencing services (involving an incident or independently of any incident, as well as a situation of vulnerability on the part of the customer (in the case of an incident caused voluntarily or involuntarily by the customer), the involvement and behavior of the actors (customers and advisers) in the management of their relationship in the event of an incident or independently of any incident, the stage 2 of development of the relationship (Period 1 linked to entry into relationship with the bank, Period 2 linked to the development of the relationship with the bank) -and the temporal aspect of the implementation of the services (before, during and after effective implementation).

1 Period 1 linked to entry into relations or Period 2 linked to the development of the relationship. 2 The notion of stage refers to the two periods of the relationship as identified by customers an financial advisers -Periods 1 and 2. Before the implementation of services (whether or not involving an incident)

As an expectation

(in a situation of vulnerability and dependence of the customer)

Before the implementation of services

Meanings of Interpersonal Trust

Since trust is a highly "contextualized" variable, it is important to view the results in the light of this characteristic. The results obtained are therefore specific to the individual customer/bank relationship. Another limiting factor relates to our sample. The customers questioned in the context of our study maintained regular "face-to-face or telephone" contact with their adviser (four times a year in meetings at the branch and every month or two by telephone). It would possibly have been interesting to have questioned customers having instead a transactional orientation and not needing to maintain a regular relation with an adviser. Such customers would have provided further information concerning possible conceptions of institutional and interpersonal trust.

Figure 3 .

 3 Figure 3. Conception and mechanisms of interpersonal trust (true trust) -(period 1)

Figure 4 .

 4 Figure 4. Meanings and mechanisms of interpersonal trust during the development of the customer/bank relationship -Period 2

  putting to the test the behavior of the actorscustomer/adviser following several experiences seen as positive) Past Satisfaction (linked to past experiences(x1, x2, x3)whether or not involving an incident) Current Satisfaction -(linked to an experience of service (x4)whether or not involving an incident)


G Petit

Yannou-Le Bris

SUSTAINABILITY FOR THE ACTORS OF A FOOD VALUE CHAIN: HOW TO COOPERATE?

Keywords: Sustainability, Indicators, Assessment, Cooperation, Value chain, Food, Actors

To tackle sustainability issues, food value chain actors have to study the nature and objectives of the sustainable performance they want to achieve, both individually and also for the value chain as a whole. But they have different interests, goals and strategies. Consequently if they want to cooperate on a shared device because this represents a possible solution to improve the value chain sustainability, they need to find a way to meet a minimum level of each actor expectations. This case study is about possibilities for actors of a pork value chain representative of one type of French production to cooperate in sharing sustainability improvement solutions. The sustainable impacts of the value chain comprising a shared methanation plant with externalization of 3% of heat and 1% of electricity produced are described and analyzed. The multicriteria evaluation of the value chain is based on a life cycle analysis model with associated environmental and social indicators. The behavior of the methanation plant is simulated using Methasim tool and the input/output flows of the software are bridged to the LCA model. A focus is made on comparing the sustainable performance of two scenarios (standard i.e. without methanation plant and with shared methanation plant) and on confronting results with respective expectations of various players of the value chain in terms of sustainable performance. Is sharing a methanation plant a good solution for the economic actors of the value chain? How to create cooperation between the actors of a value chain in order to increase sustainability of their products and practices? The results and analysis will focus on each actor's contribution to the sustainable footprint and values destroyed or created. New intermediate solutions can be then proposed. The discussion is about methodological ways to facilitate the cooperation and the data flows to be exchanged between value chain actors.

INTRODUCTION

In the food value chains, it is the transformer's or the distributor's practice which casts a decision-making power over all actors [START_REF] Jörg | Critical factors for subsupplier management: A sustainable food supply chains perspective[END_REF][START_REF] Meynard | Designing coupled innovations for the sustainability transition of agrifood systems[END_REF]. The growing demand for organic, local, "free" (antibiotics, GMO, etc.) products indicates the willingness of consumers and producers to favor alternative systems development. If labels and designations adapted to these offers are now a way to reduce the complexity of the consumer's decision, they propose a limited response for the actors of food value chains. Indeed, they constitute some specifications aimed at obtaining very specific characteristics (fed with grain, source of omega-3, rich in fiber, low in fat, etc.) and for which the global sustainability is not guaranteed. Indeed, the sustainability issues are multiple and the solutions adopted to meet them can generate other impacts, but also move some impacts from one phase to another of the life cycle. Therefore, if the implementation of labels or claims may be the starting point for the coordination of value chain actors, it can't be sufficient to go beyond simple specifications. Moreover, the notion of a label potentially carries the same power exercised by one actor on the others as what was identified in the dominant food systems. It is precisely to meet the objective of offering a multicriteria framework and limiting the risks of transfer of impacts that Life Cycle Analysis has been developed [START_REF] Jolliet | The LCIA midpoint-damage framework of the UNEP/SETAC life cycle initiative[END_REF][START_REF] Unep | Lignes Directrices pour l'Analyse Sociale du Cycle de Vie des Produits[END_REF]. In this paper two assumptions are made: first modeling a value chain and its environmental, economic and social assessment offers a systemic framework that is superior to what labels offer. Indeed, it is more valuable to the value chain actors even if the complexity of its reading makes it inaccessible to the end users / consumers. The second hypothesis exposes that this kind of model offers a common basis to the value chain actors to consider a wider reality than what their usual paradigm offers and from which new cognitive knowledge will be built. For these actors to be in a position to design together improved value chain sustainability, they need to co-design their solutions. In this perspective, the associated design and decision-making activities are considered from a socio-cognitive point of view. The construction of a solution is then not only objectified for the creation of a response to technical needs but also as a process of negotiation between different parties [START_REF] Fréard | Comprendre l'activité collaborative dans des communautés épistémiques en ligne: une approche socio-cognitive[END_REF]. In his works Bucciarelli [START_REF] Louis | An ethnographic perspective on engineering design[END_REF] defined these parties as the different disciplines that intervene in a design process. As part of this article, it is the pluralism of the various actors in the value chain that give rise to a space for negotiation. The representations offered by the value chain modeling and the assessment of its sustainability performance are then supported to create a common space for actors in the creation and coordination of knowledge, beliefs and mutual hypotheses. These two hypotheses are discussed here in the framework of an experiment that we conducted on the modeling of a French pork value chain. Its stakeholders seek to identify solutions to improve its sustainability performance. One of the solutions resulting from one of their brainstorming was the pooling of a methanation plant from a circular economy perspective within this value chain. Chapter 2 presents a synthesis of the physico-chemical phenomena involved in methanation and the socio-technical development of this technology in France. Chapter 3 illustrates the model created and the alternative scenarios considered with the integration of a methanation plant. In this chapter that we also provide the indicators used to perform the performance evaluation. Chapter 4 is the synthetic presentation of the results compared with and without methanation plant in the value chain. Chapter 5 allows us to discuss the contribution of these results to the two hypotheses. The conclusion synthesizes the contribution of this work to the validation of our hypotheses and defines the future research needs to complement the contribution presented in this article.

PHYSICO-CHEMICAL PHENOMENON RELATED TO BIOGAS PRODUCTION

AND SOCIO-TECHNICAL DEVELOPMENT IN FRANCE Methanation is a technique for the production of energy and heat by the valorization of biomass [START_REF] Moletta | Procédés biologiques anaérobies -La digestion anaérobie des effluents[END_REF][START_REF] Bernet | Caractérisation de la mise en oeuvre de la méthanisation[END_REF]. The organic bacteria present in the material allow the fermentation of this biomass and the production of biogas [START_REF] Kapseu C | Ngaoundéré[END_REF]. The biogas produced is a gas saturated with water and made of 50 to 70% methane, 20 to 50% carbon dioxide and a few trace compounds (NH3, N2, H2S) [START_REF] Godon | Aspects biochimiques et microbiologiques de la méthanisation[END_REF]. This biogas can then be recovered in the form of biomethane fuel, for the production of electricity and heat by cogeneration, in heat production alone using a boiler, or injected into the natural gas network after purification. During hydrolysis and acidogenesis, the complex organic matter (proteins, lipids and sugars) is first degraded to the simpler molecules (amino acids, fatty acids, glucose, nitrogenous bases) by the cellular enzymes present in the material. This step is sometimes limiting in the case of compounds that are difficult to hydrolyse, such as cellulose, starch or fats. These simple substrates are used at the time of acidogenesis by the so-called acidogenic microbial species which produce alcohols and organic acids, as well as hydrogen and carbon dioxide. Then, the methanogenesis step is carried out by microorganisms which operate under strictly anaerobic conditions [START_REF] Ghouali | Maximizing biogas production from the anaerobic digestion[END_REF]. They belong to the reign of the archaea and some fifty strict methanogenic species are described, all anaerobic. The production of methane is carried out by two possible routes: one from hydrogen and carbon dioxide by the hydrogenophilic species and the other from the acetate by the acetoclastic species.

Performance of methanation plants: factors of variability related to technologies and practices deployed

Organic fermentable inputs derived from biomass can be classified according to their methanogenic power: waste from the food industry, livestock effluents such as manure, straw, slaughterhouse water loaded with organic matter or sludge from sewage treatment plants, fermentable fraction of household refuse, etc [START_REF] Dario | Modélisation de la diversité microbienne dans les procédés de digestion anaérobie[END_REF]. If the slurry has a low methanogenic power, it is a substrate rich in bacteria that promotes methanation [13-14-15].

To ensure a satisfactory yield, it is necessary to add a mix of products with high methanogenic power, such as vegetables, the fat collected as scrap from the food industry [START_REF] Sialve | Prétraitements thermiques des lisiers : impact sur la cinétique et le taux de conversion en méthane[END_REF][START_REF] Benoit Jeannequin | Réduire les pertes alimentaires dans les filières Fruits, Légumes et Pomme de terre[END_REF]. Agricultural installations reuse among other things, their waste, and are based on territorial pooling models between several farms. Other inputs are added in order to obtain the best possible return in terms of electricity and heat. The nature of these inputs, which are solid or in the form of sludge, determines the dry or wet orientation of the methanation [START_REF] Rouille | Recensement des pratiques d'utilisation des coproduits par les éleveurs méthaniseurs en France[END_REF][START_REF] Buffière | Les technologies de la méthanisation des résidus solides[END_REF]. The technologies used differ according to the type of methanation (one or two stages, continuous or discontinuous, dry or liquid). The liquid or solid residue obtained from the fermentation can be upgraded as an organic fertilizer in substitution or in addition to conventional chemical fertilizers or in direct spreading when the spreading plan allows it (soil composition, geographical location and capacity of the soil). Beforehand, a standardization and homologation stage is necessary. If, however, the digestate cannot be recovered, it is destroyed: buried or incinerated. Cogeneration is the production of heat and electricity from biogas through a module consisting of a motor that drives an alternator [START_REF] Abbassi-Guendouz | Rôle du transfert de matière dans la limitation de la digestion anaérobie par voie sèche[END_REF][START_REF] Bernet | Caractérisation de la mise en oeuvre de la méthanisation[END_REF]. Electrical efficiency can rise by up to 5%, and heat output allows an overall efficiency of 85%.

Economic organization of a methanation process

The main interest of cogeneration is the resale of electricity to the grid, which has to acquire electricity at a regulated price. It can be sold to supply households, businesses or local authorities, or it can be consumed whole or in part by production sites linked to methanation. Heat is recovered by heat exchangers and can be carried by hot water pipes to industries, public buildings, hospitals, collective dwellings or offices. It can also be directly used on the spot for feeding pig farms for example. As a result, cogeneration facilities are often located near areas where there is a need for heat energy to avoid the loss of transport energy. By reducing the use of fossil fuels, heat recovery leads to a reduction in pollutant emissions such as Sulphur dioxide and greenhouse gases. Finally, unlike other renewable energies that are sensitive to climatic variations, the cogeneration energy capacity is stable over time and space, and is subject to the stability of inputs. Fuels are easily stored and potentially available: waste from bio-industries, livestock effluents. It is therefore reasonable to assume that this is a reliable response to part of the electrical demand. As for heat, which is more difficult to transport, its use requires a physical approximation of the user activity in order to make the installation cost-effective. On the other hand, and even if rates act as incentives, the relative economic profitability of cogeneration systems depends heavily on the prices of fuels and competing energies. Under good conditions, cogeneration makes it possible to recover 35% of the primary energy from biogas in the form of electricity and up to 85% in total, taking into account the heat produced by the system. In France, the cost of the investment was estimated at around € 5,700 per electric kilowatt for an average power of 250 kilowatts. The Légifrance rate order of 14 December 2016 provides for the purchase of electricity for installations with a maximum electrical power of 80 kW or less, at a price of 175 € / Mwh; For those with an electrical power between 80 kW and 500 kW, at a price of 155 € / Mwh. Beyond that, an invitation to tender is required.

The buyback contracts are established over 20 years now and no longer 15. There is no longer any obligation to recover the heat.

PRESENTATION OF THE STUDIED SYSTEM

Perimeters of the compared models

The value chain considered as a reference model describes an existing sector in which the actors involved are working to improve the sustainable characteristics of their activities and products by working on animal feed (content and proximity of supply), non-use of GMO foods, animal and human health, reduction of antibiotics and stress, increase in the cost of purchasing pigs from the farmer to take into account the efforts made and sharing the economic value created. The territorial scale considered is that of the western region of France which comprises of five administrative regions. Figure 1 shows the activities considered in our model for both scenarios: without (Scenario 1) and with methanation plant (Scenario 2). The addition of the methanation plant is represented in the figure 1 by the boxes colored pink. For the study, the hypothesis was made that in a sense of circular economy, the electricity and heat produced by the methanation plant are reinjected at the stages of the farm and the slaughterhouse; first because of their need for heat, and second because these two installations are supposed to be close to the methanation plant for the exchange of heat. However, the modeled methanation plant produces more electricity and more heat than necessary. Also, in the scenario 2 these flows in excess are sold at prevailing rates and used outside of our system. The environmental advantages of these flows production is valued as follows: in the scenario 2 the impacts associated with the production of electricity and heat (by an average source representative of the French (mostly nuclear) energy mix) were modeled then subtracted from the impacts associated with the methanation plant scenario in order to take into account the impact avoided by the production of our facility. The functional unit that sizes our model is the quantity of pig meat required for the production of 13,500 tray units of 6 chipolatas which involves breeding 600 pigs. The share of the activities and impacts related to the pig meat used in these chipolatas is dimensioned by the proportion of meat used per pig for their production.

Modeling tools used

Two modeling tools were used to conduct this study. The first one is life cycle analysis software (Simapro 8.0.5.), which allowed to evaluate and compare the environmental performance of the two scenarios. In this study, the inventory phase was carried out with real stakeholders of the French pork industry. For example, zootechnical or economic information have been collected on the ground. In order to complete this collection, the database present directly within the software databases such as EcoInvent 3 (the Swiss database) or Agri-footprint (Dutch database) were used. Finally, scientific articles and technical documentation were consulted to complete the dataset. The impact calculation phase, carried out using the Recipe 1.12 Midpoint method, widely used in the living world, made it possible to calculate specific sustainability indicators. In addition, the Methasim [START_REF] Levasseur | Développement d'un calculateur pour déterminer l'intérêt technico-économique de la méthanisation dans les différents systèmes de productions animales: Méthasim[END_REF] software made it possible to size the methanation plant and its efficiency. The latter is a decision-making tool for pre-diagnosis of anaerobic digestion: it is possible to calculate the technical and economic interest of anaerobic digestion according to the choice of inputs, methanation process, purchase cost of electricity, etc. Particular attention has been paid to the nature of valuation methods of thermal energy to target the improvement provided in the tariff policy. For the purposes of this article, a minimum of data has been imposed on the tool so as to allow the latter to suggest the solutions most suited to the system studied.

The characteristics chosen for the methanation plant considered in this study are: continuous liquid, the destination of the biogas: dual-fuel engine, the power of the cogenerator (546 kW elec), the volume of the main digester (1,807 m3). Figure 4 presents a synthesis of the project carried out thanks to the support of Methasim. These data are then used to calculate some of the indicators suggested by this study in the following sections.

Repository used to assess the sustainability of scenarios

The framework used in this study was developed by the authors in the context of work carried out prior to this study. Presentations of these papers have been made: [START_REF] Petit | Innovations in attractive and sustainable food for health[END_REF]. The authors do not have the space required to go into details on the methodology implemented and therefore propose to consider these evaluation criteria simply as a reference allowing the comparison of the two scenarios.

Data used in the model

Breeding, slaughtering and cutting phase (common to Sc1 et 2)

In this study, the inventory phase was carried out with stakeholders in the French pork industry. In addition, the database hosted by the Simapro 8.0.5 software. EcoInvent 3 (Swiss database) and Agri-footprint (Dutch database) were used. Finally, scientific articles and technical documentation were consulted to complete this dataset. The impact calculation phase, carried out using the Recipe 1.12 Midpoint method, widely used in the living world, made it possible to calculate specific sustainability indicators.

Sizing of incoming methanation plant streams (Sc2)

The size of the methanation plant is defined by the nature and quantities of inputs available for its operation.

Determination of supply volumes from distribution

A model was constructed to establish the wastes in stores on the territory in question. In our model, we retained the losses due to the partner distributor brand of our value chain (in proportion to the area of its stores in relation to the total sales area on the territory). From the INSEE (http://www.bdm.insee.fr/bdm2/index) and FranceAgrimer (https://www.rnm.franceagrimer.fr/prix?SAINOMPRODUIT; https://observatoireprixmarges.franceagrimer.fr/resultats/Pages/ResultatsFilieres.aspx?idfiliere=6) databases, the volumes of French consumption and waste [START_REF]Pertes et gaspillages alimentaires : L'etat des lieux et leur gestion par etapes de la chaine alimentaire -Rapport[END_REF], by product categories, were defined and reported proportionally to the territory concerned and to the types of Shops located in this area [START_REF] Nielsen | Nielsen trends résultats au 26 janvier[END_REF].

Complementary Inputs of the methanation plant

 The manure of a swine operation of 200 pigs.  The frying oil returned to the store by consumers after use (http://www.oliobox.be/en/solution).  The fatty waters of a specialized porcine slaughterhouse processing 3,400 head a week. Table 1 shows the values of indicators for each scenario. The Methan column expresses the gross impacts of our system for the scenario 2 while the Methan column with defalcation expresses the same impacts but alleviates the avoided impacts. It is therefore logical to find negative values. As for Table 3, Table 4 shows the contributions per actor, but for the methanation plant scenario this time. A large number of values are common, except for electricity and heat indicators that have been replaced at farm level and the slaughterhouse by the production of the methanation plant modeled. Finally, Tables 5 and6 show the values of the two scenarios, control and methanation plant, but this time as a percentage of the total value of each indicator. Values may be common except for the flow of electricity and heat for the farm and the slaughterhouse, all the contribution rates change and this for all the actors. The indicators in Table 1 show a very large disparity, particularly for environmental indicators, between the control scenario and the methanation scenarios. Impact reduction is important only when excess energy and heat are resold and used outside the perimeter. Some impacts are negative for the methanation with defalcation scenario; they correspond to a compensation of impacts related to energy and heat production by the methanation plant for the slaughterhouse and pig exploitation needs, plus the avoidance of impacts related to the production of surplus heat and energy. This energy produced comes out of our system; it is resold and used outside our system i.e. not produced by an average French mix. In consequence the difference is expected to be much less striking between the control and the simple methanation scenario than between the control and the methanation with defalcation scenario. Some indicators remain unchanged. This is the case, for example, with the occupation of urban land. The size of the various installations in the value chain does not vary between the control and methanation plant scenarios because the methanation plant is installed on existing farms and does not necessarily require an expansion of agricultural areas or new urban areas. A very large part of the social and economic indicators remain the same between the different scenarios. For example, the pH of the carcass used here to characterize animal welfare does not vary between the two scenarios. The introduction of the methanation scenario does not necessarily imply an improvement in animal welfare compared to control. The same applies to the transport of live animals between the pig exploitation and the slaughterhouse. With the introduction of the methanizer, the model considered the same agricultural exploitation, located at the same distance from the slaughterhouse compared to the control scenario. In this case, the indicator does not change. Among the economic indicators, the waste rate remains the same for the actors in the value chain, such as the slaughterhouse and the processing plant. The line losses are the same whether or not there is methanation plant on the farm in the considered value chain. Finally, the contribution analysis tables (2 to 5) show that all the values of environmental indicators are lowered thanks to the introduction of the methanation plant, in particular upstream at the level of the farm. However, since the indicators are lowered for all players in the value chain, the share allocated to farmers increases while they are responsible for 85% of the environmental impacts in our model (control scenario). We discuss in the next section how this argument can be used in favor of the farmer in the negotiation between the actors in the context of a methanation scenario introduction. The aim of this study was to discuss two hypotheses: first how modeling a value chain and its environmental, economic and social assessment offers a systemic framework and secondly how this kind of model offers a common basis to build new cognitive knowledge. The results show that, within the scope of our study and within the limit of the indicators chosen, the methanation plant solution decreases the impact on a large majority of environmental indicators. When these indicators are not diminished, at worst they are unchanged. On the other hand, a large majority of social and economic indicators remain unchanged. A small share is worsened at the breeder step: additional working time, investments and the cost of production per product. The investment is inevitable in the case of the installation of a methanation plant but depending on the case, the return on investment can be more or less long and the investment more or less subsidized. The question of return on investment will be difficult to discuss to validate our assumptions. The ROI is not presented in this table and will be effectively dependent on each scenario. However, it is an argument to be exchanged in the context of negotiation among the partners. This provides the elements that can eventually be incorporated into the content of the contracts that will be established between the actors. The indicator "Working time" must be analyzed in that sense: in our perimeter, its modification is related to the farmer's activity, which implies that he must no longer be paid only for the finished product which he helps to put into market but also for the services he rendered to the society. The type of sustainability assessment promoted here makes it possible to go further than with ecolabels. It can help to apprehend socio-economic services that extend and are justified considering the added value created by the farmer and its exploitation as superior than just meat production. It should also be noted that when the energy produced in the system is taken into account and sold and used off-system, the impacts are downright negative. In other words, the methanation plant solution makes it possible to compensate for certain impacts. This is also a service to the society which cannot appear in an eco-label but which is expressed in the model proposed in this article. The information provided by this case study allows going beyond a simple specification transmitted from the downstream to the upstream. The search for a solution seems to be facilitated when it goes through a coreflection rather than a cascade of instructions. The sharing of these representations can also enable the downstream stakeholders to better understand how they can value the work carried out by the operators upstream. It was shown how services rendered to society make it possible to extend the reflection beyond what was initially envisaged in the perimeter of the value chain alone. The contribution results tables (2 to 5) show us that the relative contributions change enormously when a new methanation solution is put in place in a value chain. In particular, the shares allocated to the farm are increasing sharply. However, the jobs associated with crops and livestock are already undergoing a serious economic, environmental and image crisis in society. It seems inequitable to bring costs, additional impacts to actors who are already weakened, while the solution benefits everyone in terms of image and cumulative impacts. Let us assume that the sustainability impacts of a product are brought to the attention of the consumer by means of direct or indirect traceability (on the product, the packaging, via a related website, a flashcode, a promission, etc.): the entire chain will be promoted, including the processor and the distributor. The benefit is not the farm but the entire value chain. It is therefore important that the risks and costs associated with setting up the scenario are shared by all players in the chain. It is reasonable to assume that, as part of the implementation of a shared methanation plant between the actors of a value chain, as in the setting up of any shared project, the responsibility of reducing the sustainability impact of this chain, costs, investments must be shared equally. Depending on the calculation of impact allocations, it is the responsibility of some of the most fragile actors to negotiate with the strongest players, often those at the downstream level, to share the benefits of image among all.

6 CONCLUSION This study has shown that, in the context of the implementation of a shared methanation solution among stakeholders in a value chain, sustainability impacts are indeed reduced or maintained overall. However, on a case-by-case basis, the different contributions vary greatly with the implementation of the new scenario. The type of model developed in this article can offer a common reference framework for the actors of the value chains analyzed in order to understand the sustainability of their products and their practices from a broader perspective than they are used to. Their perimeter of responsibility is extended and this meets the expectations of consumers. It is important for the actors to co-design their improvement solutions and to associate a negotiation process between different parties and the common reference that this type of study represents thus making it possible to create and coordinate mutual knowledge. However, within the framework of the implementation of a real project and no longer a theoretical one, finer studies requiring more data are necessary in order to refine the hypotheses, and the results. On the other hand, future research remains necessary to know the prospects of mutualisation according to the type of actors studied: here the actors already work together on the sustainability of their products. One may think that this preliminary cooperation facilitated the proper introduction of the methanation plant. Would this have been the case with two actors who have never worked together or worse, with competitors? What are the limits of this work of mutualisation and structuring of the sectors?

Figure 1 :

 1 Figure 1: Perimeters of systems modeled with and without methanation plant

Table 1 :

 1 Numerical results of each scenario by indicator Contributions of each actor of the value chain to the environmental performance are highlighted in the Table 2 (scenario 1) and the Table 3 (scenario2). The indicators, called Env1 to Env10, refer to those in Table1.

								Methane
		Indicator		Unity		Control Methane	with
								deduction
	Soc1. Carcass pH		#		5,4	5,4	5,4
	Soc2. Transport duration		h		8	8	8
	Soc3. Foodmiles / localness (local cultures)	%		91,0	91,0	91,0
	Soc4. Breeder's welfare (survey)	Score 1 to 5	2	2	2
	Soc5. Employees' welfare (survey)	Score 1 to 5	2	2	2
	Soc6. Biodiversity (number component /formula) #		5,3	5,3	5,3
	Soc7. Sensory evaluation score	Score 1 to 10	6,02	6,02	6,02
	Soc8. Omega 6 / Omega 3 ratio	%		10,7	10,7	10,7
	Soc. 9. OGM ratio		%		7,5	7,5	7,5
	Soc10. Water losses after cooking (Technol quality) %		15,45	15,45	15,45
	Eco1. Additional income paid to breeder	€		0	0	0
	Eco2. Production valorisation (losses)	%		5,9	5,9	5,9
	Eco3. Muscles rate (economical quality)	%		60,9	60,9	60,9
	Eco4. Waste (losses)		%		5,9	5,9	5,9
	Eco5. Number of hires		#		0	0	0
	Eco6. Additional work hours (-)	h		0	0,5	0,5
	Eco7. Variation of labor cost	€		0	0	0
	Eco8. Short-term investment	€/t		0	0	0
	Eco9. Long-term investment	€/t		0	20	20
	Eco10. Variation of manuf. cost per product	€		0	43,5	43,5
	Env.1. Climate change		kg CO2 eq		132 162 128 418 -1 558 775
	Env2. Terrestrial acidification	kg SO2 eq		5 034	5 023	943
	Env. 3 Freshwater eutrophication	kg P eq		53	53	47
	Env4. Human toxicity		kg 1,4-DB eq	225 389 220 041 -1 825 380
	Env5. Freshwater ecotoxicity	kg 1,4-DB eq	766	762	-934
	Env6. Marine ecotoxicity	kg 1,4-DB eq	102 937 101 246	-530 181
	Env7. Agricultural land occupation	m2a		325 076 325 076	325 076
	Env8. Urban land occupation	m2a		192	192	192
	Env9. Water depletion		m3		2 582	3 170	-4 220
	Env10. Fossil depletion		kg oil eq		20 134	18 905	-512 980
	Table 2:	Contribution results (absolute values) by actor, by indicator, control scenario
	Control scenario	Sum	Distribution Transformation Slaughterhouse	Pigs to slaughter	Feed
	Env1	132 162	1 186	3 230	3 812		53 637	70 298
	Env2	5 034	5	14	12		3 600	1 404

Table 3 :

 3 Contribution results (absolute values) by actor, by indicator, methanation plant scenario

	Methanation plant scenario	Sum	Distribution Transformation Slaughterhouse	Pigs to slaughter	Feed
	Env1	128 418	1 186	3 230	719	52 986	70 298
	Env2	5 023	5	14	3	3 598	1 404
	Env3	53	0	0	0	10	42
	Env4	220 041	6 959	20 849	175	22 217 169 841
	Env5	762	8	21	0	299	434
	Env6	101 246	6 159	17 482	167	7 062	70 376
	Env7	325 076	16	148	0	37 380 287 531
	Env8	192	51	85	0	0	56
	Env9	3 170	4	18	836	919	1 392
	Env10	18 905	424	1 087	121	4 538	12 736

Table 4 :

 4 Contribution results (percentage) by actor, by indicator, scenario 1

	Control scenario	Sum (%)	Distribution Transformation Slaughterhouse	Pigs to slaughter	Feed
	Env1	100	0,9	2,4	2,9	40,6	53,2
	Env2	100	0,1	0,2	0,2	71,5	27,9
	Env3	100	0,2	0,5	0	18,2	80,7
	Env4	100	3,1	9,2	2,2	10	75,3
	Env5	100	1,1	2,8	0,5	39	56,5
	Env6	100	6	17	1,7	7	68,5
	Env7	100	0	0	0	11,5	88,4
	Env8	100	26,8	44,1	0	0	29,1
	Env9	100	0,1	0,7	9,6	35,7	53,9
	Env10	100	2,1	5,3	5,6	23,5	63,2

Table 5 :

 5 Contribution results (percentage) by actor, by indicator, scenario 2

	Methanation plant scenario	Sum (%) Distribution Transformation Slaughterhouse	Pigs to slaughter	Feed
	Env1	100	0,9	2,5	0,6	41,3	54,7
	Env2	100	0,1	0,2	0,1	71,6	27,9
	Env3	100	0,2	0,5	0	18,2	80,7
	Env4	100	3,1	9,5	0,1	10,1	77,1
	Env5	100	1,1	2,8	0	39,2	56,8
	Env6	100	6,1	17,2	0,2	7,1	69,5
	Env7	100	0	0	0	11,5	88,4
	Env8	100	26,8	44,1	0	0	29,1
	Env9	100	0,1	0,5	26,4	29	44
	Env10	100	2,2	5,2	0,6	24,1	67,3