The calculated distance (air line) between Saint-Étienne-de-Montluc and Le Havre is approximately 176 miles respectively 283 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Saint-Étienne-de-Montluc and Le Havre has been calculated here.
Air line (approximately)
283 kilometers
153 nautical miles