School is identified as a suitable place for prevention. It has to deal with many prescriptions about health, even though the mobilization of the staff seems to be limited in this field. The place given to prevention in their activities needs to be identified more precisely in order to understand the role it can actually have in relation to the target of pupil achievement which is one of education's main missions . The object of this research is to characterize how French high-school staff contribute to the prevention of smoking. This study has been careful to put these professionals in a central position: it combines a qualitative approach with interviews, and a quantitative approach with questionnaires. We have used an activity analysis model (OK) to show that determinants of involvement are structured in relation to the institution, personal practices, and the profile of the pupils. We show that prevention does not mean inculcating "good practices". Staff need to integrate the links between education and health. Indeed, it's difficult for prevention to be anchored (rooted) in the activity of these school professionals. High school staff only sporadically manage to link their educational mission to their action in the field of prevention. We give suggestions about possible training areas, which would make it possible to professionalize prevention. In this way, professionals will have to take account of the complexity of the question of prevention, as well as the professional identity of the various actors. The place given to prevention in their professional activity calls for a specific support process, while at the same time being careful to take into account the institutional and personal dimension, as well as the pupils themselves.
