National audienceThis article presents the results of a study on the evolution of modes of control between buyers and suppliers in the Maurienne valley in the nineties. The social control which had prevailed until then was replaced by a market control. Due to the rationalisation of the costs in the buying firms, this change lead to a decrease in prices. However, the amelioration of the global purchasing performance of the clients is more discussed. The study shows that a social mode of control which does not rely on formal mechanisms is fragile because it cannot prove its performance.L'article présente les résultats d'une étude sur l'évolution des modes de contrôle entre clients et fournisseurs dans la vallée de la Maurienne dans les années...