Cannes and Provence - Child Friendly Activities?

[ElisMum23]

We have two stops on our cruise, Cannes and Provence, and aren't sure what to do. We have tours planned on all our other ports. My family isn't very into galleries or artsy type things. We will probably end up eating on the ship so not really looking for a place to eat those days. We are hoping that these days would be more calm and relaxing days. Maybe the beach, somewhere to get some fun candy, something child friendly would be wonderful. We are traveling with our 8 year old son and nothing we have planned so far is extremely appealing to him. If anyone can point me in the direction of something very cheap, even free, fun, relaxing, close to port things to do that would be so wonderful!