The sociology and anthropology of labor have long drawn attention to the ways employees exercise control over the work process, including in contexts where strong orders are, given. The control of work is, in fact, an aspect of how participation and involvement in a collective organization are managed. Workers try to manage their participation (always collective but to varying degrees) in a firm in order to make work a gratifying or at least bearable experience. This involves at least three sorts of. interventions linked to practical interests: managing relations with colleagues; managing the execution of tasks and activities; and managing relations with the staff. Focusing on the actor's viewpoint and objectives, this research based on participant observation examines how workers try to act so as to facilitate their activities in the short or middle run. Their efforts sometimes correspond to what the hierarchy expects but, at other times, to a form of rebellion. (c) 2006 Elsevier Masson SAS. Tous droits reserves.