The present operation, located at 3, rue du Pont des Chèvres and 29, 31, 33, 35 and 37, Boulevard Herriot in Bourg en Bresse, consists of the rehabilitation of 118 collective housing units in occupied site, and includes the thermal rehabilitation of buildings but also maintenance, security and improvement of interior equipment. The objective of this heavy rehabilitation is the upgrading of the technical and envelope elements of the building in order to guarantee all tenants a better comfort of use and thermal of their housing. It is a question of controlling the energy expenditure of buildings from which arises a strong environmental issue.