The Compagnie du Paris-Orléans (PO) commissioned the Gentilly station in 1891, when the Sceaux line was put on normal track gauge (before the Ligne de Sceaux used a special large gauge).It was a simple halt, perhaps an enlarged gatekeeper's house.

It is located at the end of the tunnel dug from 1935, during work to remove the level crossings of the Sceaux line, by engineers from the Compagnie du PO.

Indeed, the removal of the level crossing which cut the boulevard Jourdan at the level of the Cité Universitaire required major works including the creation of a 520-meter underground tunnel passage under the City park and the reconstruction of the Gentilly and Cité Universitaire stations .

Established at an altitude of 72 m, Gentilly station is located on the RER B line, in the eponymous town, in the immediate vicinity of the "Periphérique" and therefore of Paris.

It is built just outside the tunnel from Paris, in a trench open, in a slight upward curve with 2 lateral platform.