The judicial system in France is fundamentally different to that in the United Kingdom and the U.S.A. Rather than the adversarial system, where police investigate, and the role of the courts is to act as an impartial referee between prosecution and defence, in the French inquisitorial system the judiciary work with the police on the investigation, appointing an independent juge d’instruction entitled to question witnesses, interrogate suspects, and oversee the police investigation, gathering evidence, whether incriminating or otherwise. If there is sufficient evidence, the case is referred to the procureur – the public prosecutor who decides whether to bring charges. The juge d’instruction plays no role in the eventual trial and is prohibited from adjudicating future cases involving the same defendant.
The French have two national police forces: the police nationale (formerly called the Sûreté), a civilian police force with jurisdiction in cities and large urban areas, and the gendarmerie nationale, a branch of the French Armed Forces, responsible both for public safety and for policing the towns with populations of less than 20,000. Since the gendarmerie rarely has the resources to conduct complex investigations, the police nationale maintains regional criminal investigations services (police judiciaire) analogous to the British C.I.D.; they also oversee armed response units (R.A.I.D.).