Based on the variance of the social characteristics of students in all French universities between 2007 and 2011, this article suggests that their social origin is sufficient to account for a disciplinary space and the disciplinary groupings that strongly overlap with the classification by groups of the National Council of Universities. This overlap, confirmed by other characteristics such as gender or educational capital, justifies the assumption that the more or less explicit hierarchies between fields of knowledge, usually premised upon epistemological or practical arguments, correspond with class-based social judgments.