The calculated distance (air line) between Lille and Boulogne-Billancourt is approximately 129 miles respectively 208 kilometers.
By car or train, the actual journey to Boulogne-Billancourt is certainly longer, as only the direct route (as the crow flies) between Lille and Boulogne-Billancourt has been calculated here.
Air line (approximately)
208 kilometers
112 nautical miles