 Later shifting to the social sciences, he received his M.A.from the University of Paris, and his PhD from the École des Hautes Études en Sciences Sociales, writing his thesis on power relations and health inequalities in Senegal.After having been granted a fellowship by the French Institute for Andean Studies to investigate maternal mortality and living conditions among Indian women in Ecuador, Fassin became professor of sociology in 1991 at the University of Paris North.