The calculated distance (air line) between Montigny-lès-Metz and Frouard is approximately 23 miles respectively 37 kilometers.
By car or train, the actual journey to Frouard is certainly longer, as only the direct route (as the crow flies) between Montigny-lès-Metz and Frouard has been calculated here.
Air line (approximately)
37 kilometers
20 nautical miles