The calculated distance (air line) between Rennes and Rueil-Malmaison is approximately 185 miles respectively 297 kilometers.
By car or train, the actual journey to Rueil-Malmaison is certainly longer, as only the direct route (as the crow flies) between Rennes and Rueil-Malmaison has been calculated here.
Air line (approximately)
297 kilometers
160 nautical miles