The architectural heritage of the medina of Rabat, in Morocco, was preserved, from the first years of French Protectorate (1912-1914), in application of the will of the first general Resident, Hubert Lyautey, who wished to protect the Arab-Muslims cities having a pronounced historical, aesthetic or picturesque character. The implementation of this policy is delegated to the Service of Antiquities, Fine Arts and Historic monuments the main purpose of which is the classification and the protection of historic monuments as well as controls it developments of the medina in order to preserve the aesthetic aspect of the latter. In this mission, the Service is helped by the municipality of Rabat which also has the load of the interview of the public road network to improve the living conditions in the medina. Achieving all these objectives requires the promulgation of a corpus of rather binding rules of town planning. These regulations will be questioned, from 1935s, notably because of the fast increase of the population living in the medina which threatens the conservation of the Arab-Muslim city. The colonial administration will try then, until the end of Protectorate in 1956, to find solutions to demographic, social problems and of town planning with which the historical city is confronted from now on.