The present operation, located at 1, 2, 3 and 4 rue Jemmapes and 1 and 3 rue Solférino in Bourg en Bresse, consists of the rehabilitation of 3 buildings comprising 40 collective housing units on an occupied site. This operation provides for the thermal rehabilitation of buildings as well as maintenance, safety and upgrading 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. The environmental challenge is significant thanks to the control of the energy expenditure of buildings and the impact on the reduction of greenhouse gas emissions.