The calculated distance (air line) between Châteaubriant and Paris 15 Vaugirard is approximately 186 miles respectively 299 kilometers.
By car or train, the actual journey to Paris 15 Vaugirard is certainly longer, as only the direct route (as the crow flies) between Châteaubriant and Paris 15 Vaugirard has been calculated here.
Air line (approximately)
299 kilometers
162 nautical miles