The calculated distance (air line) between Marcq-en-Barœul and Le Havre is approximately 155 miles respectively 249 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Marcq-en-Barœul and Le Havre has been calculated here.
Air line (approximately)
249 kilometers
134 nautical miles