Studying the history of psychiatry from a gender point of view is now a classic genre in the English-speaking academic world. However, there is no such historiographical tradition in France, where only a very few studies have been written on the subject so far. The aim of this project was thus to take a fresh look at the French history of psychiatry, by exploring how the evolution of theories on gender differentiation have altered the management of the insane in the modern period. Psychiatry mainly targeted women. However, asylum statistics indicate that—at least in France—more men than women were locked up in psychiatric institutions. It is only at the beginning of the twentieth century that the ratio of men and women started to reverse, so that the asylum female population was sometimes 30 percent higher than male in the interwar period. This study sought to explain this major shift in the psychiatric treatment of men and women in France by following the medical discourse on madness, as well as the treatment of female criminality. Furthermore it takes into account a "female invasion" in the psychiatric profession. In tracing the scientific legacies of the first female French psychiatrists, the examined whether female psychiatrists developed new ways of seeing madness, whether women doctors changed the functioning of the asylum institution, and what patients themselves thought of their presence.