The calculated distance (air line) between L'Haÿ-les-Roses and Rouen is approximately 72 miles respectively 116 kilometers.
By car or train, the actual journey to Rouen is certainly longer, as only the direct route (as the crow flies) between L'Haÿ-les-Roses and Rouen has been calculated here.
Air line (approximately)
116 kilometers
63 nautical miles