The calculated distance (air line) between Douvres-la-Délivrande and Rennes is approximately 101 miles respectively 162 kilometers.
By car or train, the actual journey to Rennes is certainly longer, as only the direct route (as the crow flies) between Douvres-la-Délivrande and Rennes has been calculated here.
Air line (approximately)
162 kilometers
88 nautical miles