The north department is particularly well supplied with penitentiaries. The period of the Third Republic produces various laws which worry about "how to lock" but also about "who to lock". Where from the question : in what measures theses laws influence the prison park and their occupants ? The key law of June 5th, 1875 which confirms the attempt missed the cellular under the July Monarchy, feeds long debates before teaching at the very beginning of the XXth century the opening of two cellular prisons in the north department. This research shows that these establishements do not bring a blatant improvement of the conditions of detention. If improvement there was, it is rather thanks to the reduction in staff. Only the treatment of the young prisoners testifies of an evolution in the recourse to the confinement and, more shyly, in her daily organization of their confinement. The emergence of the prevention is made to be more determining fotr this category of citizens. This research also testifies of the prison, the life from day to day within establishments. This thesis makes one modest contribution to the prison history and to that of the treatment of the crime. Her peculiarity is especially in the quasi-exhaustive exploitation of the various series of departmental archives concerned to this subject.
