The Canal d’ille-et-Rance in Dept 35 Ille-et-Vilaine is a narrow gauge canal that is 79KM (49 miles) long that runs from Rennes to St Malo. Construction work started in 1804 and the canal was first used in 1832 there are 48 locks along its route. I have listed the towns were the Locks are so you know the route of the Canal – Rennes , St Gregory , Betton , Chevaigne , Melesse , Saint Medard sur ille , Montreail sur ille , Guipel , Hede-Bazouges , Tinteniac , Quebriac , Saint Domineuc , Treverien , Evran , Calorgue , Saint-Carne , Dinan and Saint Samson sur Rance. There is a run of 11 locks at Hede-Bazouges so is worth a visit on its own. The whole canal is good for general fishing but there is also very good Pike and Carp fishing to be had. For fishable areas you will have to look at local signs also about night fishing.
Please note – When fishing any Public waters in France please have respect for the location and clear up any mess that you have made and do not damage banks / vegetation and no open fires, Catch and release all fish except Trout and Salmon that rules let you take and when fishing for Carp use appropriate fishing tackle with large landing net and unhooking mat. Fish stealing is a big problem from Public waters if you see anybody removing large fish like Carp please take note of the vehicle registration and report to authorities.