Boulogne-Billancourt (French pronunciation:[bu.lɔɲ.bi.jɑ̃.kuʁ]; often colloquially called simply Boulogne) is a commune in the western suburbs of Paris, France. It is located 8.2km (5.1mi) from the centre of Paris. Boulogne-Billancourt is a subprefecture of the Hauts-de-Seine department and the seat of the Arrondissement of Boulogne-Billancourt.