Marcel Allain was a French writer mostly remembered today for his co-creation with Pierre Souvestre of the fictional arch-villain and master criminal Fantômas.
The son of a Parisian bourgeois family, Allain studied law before becoming a journalist. He then became the assistant of Souvestre, who was already a well-known figure in literary circles. In 1909, the two men published their first novel, Le Rour. Investigating Magistrate Germain Fuselier, later to become a recurring character in the Fantômas series, appears in the novels.