The town was formerly named Châtillon-sous-Bagneux, and a relic of this denomination remains in at least one road sign in Vanves (located at the junction Boulevard du Lycée and Avenue Charles de Gaulle, and written as Châtillon s/ B).

[3] In 1417, during the Armagnac–Burgundian Civil War, John the Fearless, Duke of Burgundy, camped at Châtillon for eight days while his army pillaged the surrounding villages before laying siege to Montlhéry.

During that year a quick and lively engagement with enemy English and Prussian troops took place near the tower.

Châtillon enjoys a well connected bus service: from Paris, the 68 comes all the way from the Place de Clichy to the metro station.

Buses 194, 195 and 295 all leave Porte d'Orléans and pass by the Châtillon – Montrouge metro station from where they continue mostly in different directions.