Résumé (EN)

This article questions the absence of scientific assessment at the time the Institut d’urbanisme was set up as part of the University of Paris. An analysis of the epistemological aspects of the project and the context of the period shows that, despite the lack of theoretical certitudes to underpin the discipline of town planning, it was nevertheless based on a number of legitimate sources and, at the same time, crystallised the social stakes involved. Academics involved were all the more ready to accept this powerful social image as they all had connections with town planning, which testifies to the role played by extra-scientific criteria in the judgement of professors at the time.