Boulogne-Billancourt is a wealthy and prestigious commune situated in the western inner suburbs of Paris, France. Located approximately 8.2 km (5 mi) from the center of Paris at Notre Dame, it serves as a subprefecture of the Hauts-de-Seine department and functions as the seat of the larger arrondissement of Boulogne-Billancourt.
The commune is an integral part of the Métropole du Grand Paris. Geographically, it includes one island situated within the Seine river known as Île Seguin.