The calculated distance (air line) between Romainville and Fontenay-sous-Bois is approximately 3 miles respectively 5 kilometers.
By car or train, the actual journey to Fontenay-sous-Bois is certainly longer, as only the direct route (as the crow flies) between Romainville and Fontenay-sous-Bois has been calculated here.
Air line (approximately)
5 kilometers
3 nautical miles