The Lyon Confluence project is an actual urban planning operation of Lyon agglomeration. It is part of a global sustainable development process, mixing economic development, social equity and preservation of natural resources. Due to ambitious requirements in term of energy consumption level and indoor thermal comfort, the project implies a new way of thinking in the design of French construction. The consortium composed for this project brings together national and European-level expertise for finding solutions to insulate and also avoid overheating during summertime without conventional cooling system. During the phase of building conceiving numerical simulations have been led by the CETHIL on the software TRNSYS in order to check (energy consumption and thermal comfort) each architect proposal on the whole area. In case of detected non satisfying design, Lyon consortium was in charge of imposing different way of improvement. The modeling and study of one apartment show how important is to increase the free cooling by natural ventilation during the hot period. This paper presents the ambitious standards that have to be respected into this new project in France. It shows the propositions and the research that are actually in progress on the topic of high efficiency buildings.