CRENAU Researchers : Anne Bossé, Marc Dumont, Pauline Ouvrard. This report, conducted by a french social science research team (LAUA, Nantes school of architecture) directed by Laurent Devisme, PhD in planning, aims at a global perspective on modelling activities in the scope of urban and environment matters. One of the main hypotheses is that climate change and sustainability paradigms have led to new models that may have important consequences for urban models and in the end for planning communities. For both the PUCA (French ministry of ecology) and the GSF (OECD), the study is based on qualitative materials coming from interviews, questionnaires (a list of more than a hundred potential experts has been constituted, mainly researchers but also laboratories managers and funders, rarely users) and bibliographical investigations.