Canal du Midi
In May 2016 I biked with my wife from Toulouse to Sète along the Canal du Midi. Afterwards we had some mixed feelings. Some parts are very nice bust some are not due to the absence of trees. The tow path is mostly clay and tree roots make it often difficult to ride on, even in dry weather. After a shower, it becomes very unpleasant. We only had rain in Béziers (a dreadful city) and the path became impassable due to the clay sticking to the weels. Close to the Mediterranean you can find alternative roads however. Earlier on the path this is much more difficult and dangerous.