The calculated distance (air line) between Rouen and Saint-Maur-des-Fossés is approximately 77 miles respectively 125 kilometers.
By car or train, the actual journey to Saint-Maur-des-Fossés is certainly longer, as only the direct route (as the crow flies) between Rouen and Saint-Maur-des-Fossés has been calculated here.
Air line (approximately)
125 kilometers
67 nautical miles