The calculated distance (air line) between Saint-Mandé and Maisons-Alfort is approximately 2 miles respectively 3 kilometers.
By car or train, the actual journey to Maisons-Alfort is certainly longer, as only the direct route (as the crow flies) between Saint-Mandé and Maisons-Alfort has been calculated here.
Air line (approximately)
3 kilometers
2 nautical miles