First Professor of Cutaneous and Syphilitic Diseases at the Paris Faculty of Medicine in 1879,
Fournier was an exclusive and internationnally know Master of syphilis, a disease regarded in
the 19th century as a medical and social plague.Head of a department at the Hôpital de Lourcine (today hôpital Broca), specialized in the treatment of the syphilitic women, Fournier was then appointed in Saint-Louis in 1876, successor of Alfred Hardy.
In opposition to most theories of his time, Fournier demonstrated the syphilitic origin of tabes and general paralysis only on the basis of clinical observation without the assistance of serologic tests later invented.
In 1901, he was the founder of the "Societé française de prophylaxie sanitaire et morale" a melting pot of medical, social and political reflexions about the treatment and prevention of the sexually transmitted diseases.
Among his numerous publications, "Syphilis and marriage" in 1880, "The parasyphilitic diseases" in 1894 and "Textbook of syphilis" 1899, have to be quoted.