International audience Since the creation of the French Republican school at the end of the nineteenth century, the mode of production of educational inequalities has changed profoundly. While educational inequalities were at first a direct consequence of social inequalities, in the mass democratic school system they are continuously produced by an aggregation effect of small inequalities. Over the last century, the conception of educational justice has also been profoundly transformed under the influence of the equal opportunities model. Nowadays, the contradictions of this model of justice structure French debates on education. Keywords: education, educational inequalities, equality of opportunities, social inequalities, sociology of the school system.