Boulogne-Billancourt (French pronunciation: [bulɔɲ bijɑ̃kuʁ]; often colloquially called simply Boulogne, until 1924 Boulogne-sur-Seine) is a commune in the western suburbs, and 8 km (5.0 mi) from the centre, of the French capital Paris. Boulogne-Billancourt is a subprefecture of the Hauts-de-Seine department and the seat of the Arrondissement of Boulogne-Billancourt.