Toulouse is not too bad. The Canal Lateral meets the Midi at a big pool, and the towpaths go right through the middle of the town. The local roads are often very busy. The towpath surface is quite often gravel, and i have sometimes found mooring ropes stretched across the path.
I haven't ridden there in seven years, so can only give a view of what it was like back then. The canal goes right past the town station (Matauban, IIRC) and that bit, and around Rue Riquet, is a red light area.
My wife's brother lives there now so hopefully we'll be going at least once a year. We rode part of the canal path 2 years ago, & it was better than the Grand Union which we ride when the Amazon jungle parts are cleared :-)
It's also not bad around the City, & much better than by car.