Enterprise and management of the aging workforce: organization, discrimination.

Summary The unfavorable situation of aging employees on the labor market leads us to question the economic mechanisms that generate this inequality. The objective of this thesis is to contribute to their explanation through a microeconomic analysis of the behavior of firms with respect to these employees, focusing on the practices that contribute to differentiate individuals within the firm: recruitment, training, promotion and termination of the employment relationship. Discrimination theories are taken as a starting point. Different models explaining the role of the firm in the evolution of workers' productive characteristics are then mobilized (human capital, tournaments, deferred payment contracts, internal market). Finally, the implications of the training and promotion practices highlighted on the practices of breaking the employment relationship and recruitment are analyzed (models of Parsons, Oi and Stankiewicz, deferred payment contracts, internal markets). In order to understand the diversity but also the coherence of firms' behaviour, it is necessary to take these practices into account simultaneously, hence the construction of configurations of practices based on the models already used, supplemented by the analysis of Aoki. These configurations are then compared with the configurations observed in France using two types of data: - monographic data on six establishments, collected in 1993 and 1994, - data resulting from the matching of a postal survey carried out in 1991 on the management of ageing wards with the EMMO-DMMO surveys. These data, which can be used for 1,112 establishments, are subjected to a principal component analysis, a hierarchical ascending classification and logistic modelling. Nine categories of establishments are analyzed, highlighting a very large differentiation in company behavior.