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Boulogne-Billancourt Subprefecture is the seat of the larger arrondissement of Boulogne-Billancourt, a commune in the Hauts-de-Seine department in the Île-de-France region, France. Located on the western outskirts of Paris, the arrondissement encompasses the city of Boulogne-Billancourt and several smaller communes. It is known for its industrial heritage, particularly in the automotive industry, and its transformation into a vibrant cultural and business hub.