In 1876 he resigned his commission to enter the Chamber as deputy for Nantes in the republican interest, and in 1879 he became director of the Le Petit Parisien.

Laisant published two political pamphlets, Pourquoi et comment je suis Boulangiste (1887) and L'Anarchie bourgeoise (1887).

[3] Already in 1874, he published a survey on hyperbolic functions[4] as well as a French translation of Giusto Bellavitis main paper on equipollences into which Laisant added a chapter on hyperbolas.

[7] He also co-founded a mathematical journal, L'Intermédiaire des Mathématiciens with Émile Lemoine in 1894, and was in 1888 the president of the Société Mathématique de France.

[3] The pedagogical journal, L'Enseignement Mathématique, founded by Laisant and Henri Fehr in 1899, became the official organ of the International Commission on Mathematical Instruction in 1909.