The calculated distance (air line) between Mont-Saint-Martin and Marne La Vallée is approximately 150 miles respectively 241 kilometers.
By car or train, the actual journey to Marne La Vallée is certainly longer, as only the direct route (as the crow flies) between Mont-Saint-Martin and Marne La Vallée has been calculated here.
Air line (approximately)
241 kilometers
130 nautical miles