Bearing in mind the different sociological works and political sciences that have been interested in North African militancy in France over the past twenty years, and after having proposed a sociological definition of militancy, this article examines the motivations that incite young North Africans in France to engage in politics, and to the meaning they give to this political action. After briefly recalling a certain number of theories on collective action, it analyses the militancy that mobilizes both individualistic and collective points of view. It then exposes a typology of the causality of militancy in young people of North African descent starting with these three criterions: the triggering event, the situation and the inter-acquaintance network, and presents three kinds of militancy observed during this study: career event-driven militancy, occasional situational militancy and career inter-acquaintance militancy.