Coming from Nantes take the exit Vigneux de Bretagne/ Saint-Etienne de Montluc see the map below.

To it's address - from here

Coming from Saint-Nazaire / Vannes take the exit Le Temple de Bretagne, go through the center of
Le Temple de Bretagne turn left at the traffic lights (signposted Vigneux de Bretagne) see the map below.

To it's address - from here