International audienceFrom 1944 to 1962, the scientific section of the École normale supérieure de la rue d’Ulm found its way out of the ambiguities surrounding its function: starting as a high school teachers’ seminary – and, as such, a starting point for many university careers since the 19th century –, it became an institution focused mainly on the production of researchers and faculty professors, in the wake of the historical mutation of the career horizons open to the normaliens. This article intends to study the conditions and the consequences of such a profound transformation, building on three major sources: the archives of the institution and its actors; a prosopographical study of the 539 scientific normaliens admitted from 1944 ...