Hi,
Here you can find the nudist beaches in Cannes and close to it
https://en.plages.tv/naturist/l-cannes-06400Personally, I went to "plage batterie", the biggest one (there are 3 of them), easily reachable. Not so big, but with sand and pebbles, nice and clean, the sea as well. Mostly crowded by couples or single guys, few families.