French psychiatry around 1850 is characterized by the paradigm of unitary alienation (Pinel, Esquirol), the preeminence of the moral treatment, the secondary function of the brain (after the decline of the works of Georget and Bayle and of the phrenology), the development of the asylum system (distinct from general hospitals), the theoretical rivalry between sensationalism or ¡°physiology¡± (Cabanis) and spiritualism or ¡°psychology¡± (Maine de Biran). The founders of the Soci¨¦t¨¦ M¨¦dico-Psychologique (Baillarger, Moreau de Tours, Brierre de Boismont) are inspired by the latter, politically conservative, beside their inquiries about the central nervous system. After a slow genesis, between 1843 and 1852, the society begins its reunions during the ¡°authoritary¡± period of the 2nd Empire. They are characterized by the clinical (on monomania and hallucinations) and forensic discussions between alienists and philosophers around free will. During the decade 1860, the organic theories prevail, through hereditary degeneration (Morel), strengthened by the growth of fundamental sciences and cerebral anatomo-physiology. On the other hand, discussions on classifications and ¡°folie raisonnante¡± allow the transition towards the paradigm of mental illnesses (J. Falret), later adopted in Germany by Kraepelin.