The hypermarket, in the form known since 1963, is the result of a long and complex innovation process driven by the growth of mass consumption. The founders of Carrefour drew on former experience in self-service, discounting and supermarkets to develop a specifically French form of commercial organization summed up as '?everything under the same roof'. The author completes his analysis of the group's genesis by that of the employer culture and of the type of management which guaranteed the success and diversification of the model as it spread.