The calculated distance (air line) between Nort-sur-Erdre and Le Havre is approximately 160 miles respectively 257 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Nort-sur-Erdre and Le Havre has been calculated here.
Air line (approximately)
257 kilometers
139 nautical miles