The calculated distance (air line) between Ars-sur-Moselle and Mondelange is approximately 13 miles respectively 21 kilometers.
By car or train, the actual journey to Mondelange is certainly longer, as only the direct route (as the crow flies) between Ars-sur-Moselle and Mondelange has been calculated here.
Air line (approximately)
21 kilometers
12 nautical miles