This article aims at exploring again the relationship between legitimate violence and the police. Based on an original sociological investigation of the General Inspection of Services (IGS, also called “the police of the police services”), it deals with the police force through the study of the accusations of illegitimate violence made against police officers. The reasons why few of these accusations lead to administrative sanctions are linked to the way investigations are conducted. Actually, the police acts which are the most severely condemned are the ones which undermine the public nature of police action. This paper shows that sociological studies of the police should not only examine the classical issue of the legitimate use of violence, but also seriously question the way the public nature of police action constraints it.