This article examines the thinking of Jean Izoulet (1854-1929), a French “social philosopher” close to moderate Republican circles, professor at the Collège de France, where he was appointed in large part to counterbalance the growing success of Durkheim. Izoulet’s thought, the scientific nature of which is debatable, supports social hierarchy and the legitimacy of the elite; it is constructed explicitly against Durkheim, both against The Division of Labor in Society and then against The Elementary Forms of Religious Life. The one-sided polemic that Izoulet develops against his colleague is based on an epistemological confusion: the very concept of “society”, in his writings, is confused with that of “city” or of polis, a sign that he has not seen the methodological specificity of Durkheim’s emerging sociology. On an ideological level, Izoulet’s case embodies the reluctance of the most conservative republicanism against socialism in the making; we find traces of it in Pétainism.