The long-term depletion of fossil fuel resources and the need, in front of the challenge of climate change, to reduce greenhouse gases leads to energy transition. This new energy and environmental paradigm defines from now on the context in which the city of tomorrow must be built and implies to consider a new space organization that would bring about the sustainable city. Households and companies choices of location contribute to shape the spatial organization of the city. Those choices are now in total contradiction with the new energy, environmental, economic and social requirements. If households and businesses plebiscite of suburban areas is clearly in conflict with the principles of urban sustainability, it is still possible that new environmental and energy constraints will not be enough in themselves to influence private actors spatial dynamics. On the environmental front, the double movement of jobs and residences dispersal to suburban areas made possible by widespread access to an automobile mobility at low costs contributes to increase greenhouse gas emissions. These are related to higher energy consumption of transport and housing, reflecting the longer distances traveled by car and by the expansion of living space linked to the preference for individual house. On the social front, individual home ownership in suburban areas where land is cheaper proves for some households likely to carry an increased instability. Households budgets are already burdening budgets because of transportation costs and indebtedness generated by housing acquisition. This situation threatens to be reinforced in forthcoming years by the sharp rise in energy costs, energy vulnerability accentuating the social vulnerability of some households. Finally, on the economic front, employment easing from center to periphery, an easing both chosen and sustained by businesses, results often in a deterioration of the access to employment for the least qualified employees. In a context of rising energy costs, this situation could pose problems for some employees but also to companies, which, in addition to having to reconcile economic imperatives and environmental requirements, may face problems of recruitment and loyalty of their workforce. In a context marked by a new energy and environmental paradigm, the TRANS-energy project objective is to provide researchers and practitioners with knowledge of households and businesses coping strategies and their contribution to the challenge of reducing greenhouse gas emissions. This project is based on comparative work conducted on the cities of Lille and Lyon. TRANS-energy project is based on a systemic approach, both exploratory and comparative which allows, through a prospective approach, to analyze households and businesses facing these new energy, environmental economic and social constraints abitrations. In addition to the coordination task (T1) the project is structured around four complementary tasks: an analysis of Lille and Lyon spatial organization conducted from various statistical databases (general censuses, household travel surveys, SIRENE files) (T2), a field survey of firms choices of location taking into account the constraints of mobility of their employees (T3), and a field survey of workers of these enterprises and households in homeownership choices of location as well as their mobility patterns and use of housing will be carried (T4). In parallel to these tasks will be carried out methodological work on measuring CO2 emissions generated by households (T5) at a macro level, in conjunction with Task 1, then at the micro level, in conjunction with Task 3.