

Abstract
Given the widespread use of contingent labor — whether subcontracted, temporary workers, consultants or interns — a firm’s “internal” employees often work on teams with these contingent “external” wage-earners. Work teams are increasingly composite. How to understand the specific problems of cooperation in this sort of situation? Conducted in a large French firm from 2009 to 2011, a study of two mixed work teams serves to illustrate the key role played by “mediators” and the firm’s relations with them.