André Corboz in his article «A good use of historical sites» develops a model of city planning based on the conservation of cultural goods. Considering Corboz model of city planning as a critical alternative to the productive rationality of common urbanization, the paper tries to answer the question of what is ''the industrial'' in former industrial cities, both in terms of preservation of industrial heritage and with regard to current urban planning policies like sustainable development. The purpose is to question the appearance of new territorial policies of urban renewal for former industrial sites in which the industrial heritage is associated with sustainable urban planning programs and citizen engagement. The research proposes a critical examination of two programs of territorial transformation of industrial brownfields into sustainable neighborhoods in two French cities, Nantes and Saint-Ouen, by focusing on the preservation of industrial heritage within the context of sustainable urban planning policies. The two cities faced a significant population decline during the deindustrialization era but the collaboration of inhabitants, local authorities and enterprises led to urban growth while maintaining the traces of their industrial past. We must underline the originality of the research because today there aren't many researches that are doing the connection between the preservation of industrial heritage and the questions of sustainable development and citizen engagement at territorial level which could lead to new models of city planning for deindustrialized cities. The research is organized in two axes. The first axe examines the preservation of the historical identity of the two cities. This identity includes the architectural and social heritage which can be identified in the organization of neighborhoods where lived the industrial workers. The work of local associations either of former industrial workers or scholars interested in the industrial heritage led to a memory culture through the rehabilitation of former industrial buildings, publications and expositions regarding the working conditions and social life of former industrial workers. The second axe examines the future of the two cities by considering that the projects of urban renewal could potentially lead to an urban growth at a more moderate pace that respects the industrial heritage of the two cities. This urban growth model is defined in the research as a combination of modern economic activities (research institutes, eco-friendly industries) and the projection and redevelopment of industrial heritage (industrial museums, guided visits of the local industrial monuments). The research method is descriptive-analytic. The descriptive method is used in order to define memory culture and relate it to previous studies in deindustrialized cities. The analytic method is used in order to identify the reasons that led to population decline and the correlations between sustainable urban development, citizen engagement and projection and redevelopment of industrial heritage. The performed analyses included a combination of statistics techniques (diagrams of demographic evolution) and qualitative methods (interviews with local authorities, inhabitants, teams of architects and urban planners of the two projects and scholars working on the local industrial heritage). We must interline the role of the inhabitants, the local enterprises and professional associations in the preservation of the industrial heritage of the two cities. The two case studies show us that the active involvement of the local society in the projects of urban renewal could lead to new models of architecture and city planning that focus on the needs of users while preserving the traces of the industrial past. The final conclusion of the research is that the goal of urban growth in former industrial cities could be reached by applying a sustainable urban planning model which combines modern economic policies while preserving the industrial heritage of these cities.