Named after the town hall of Les Lilas ('the lilacs').
The town owes its name to the flowering gardens that covered the hill under the Second Empire, but above all to the lilacs around the guinguettes (open-air taverns), cabarets and eating houses where the novelist Paul de Kock found inspiration. When the commune was created on 24 July 1867, the names Napoléon-le-Bois and Commune-de-Padoue, after a duke of Padua who had once lived there, were also considered.