Over the past twenty years, a series of new jobs have emerged at the interface between social prevention, mediation and repression. These professions blur the boundary between policing and social control. The question is whether these new agents actually help to regulate collective spaces, in other words to prevent disorders, resolve conflicts and promote forms of living together. Based on a study of the night security agents in Paris (France), this article examines their role on the basis of the skills they are able to mobilize, their presence in neighbourhoods and their participation in local partnerships. The authors question the ambivalences, paradoxes and weaknesses of these new jobs and, therefore, the difficult renewal of public safety functions.