I've cycled the Cote D'Azure a couple of times. I believe I came down the N7 to Frejus or St. Raphael, then onto the N98 to Menton. I believe the N98 is called the Lower Corniche. Anyway, it's certainly possible, and often enjoyable, to ride the French Riviera. You won't be the only cyclist on the road, especially on a Saturday. The local drivers seem used to sharing the road with cyclists out on training rides. There are a few tight squeezes near Monaco. Just give the buses and Rolls' the right of way, and all will be good. You won't record any personal bests on this stretch of road, but it's a lot of fun to ride. After Menton, the Italian Riviera is less enjoyable (tunnels, blocked sea views, fewer Rolls'). Have fun.