We weren't huge fans of the stops in France. Cannes was a beautiful city, very fancy. There wasn't too much to see in our books. We didn't do the casino (which seemed like the popular thing to do at this port). At this port, we had to sign-up ahead of time to do a tender boat...which by the way those things can be terrifying if you don't like narrow, tight spaces! The tender was free. We walked around a bit and then spent the rest of our time laying on the beach.
We loved this stop! We decided to do this one on our own. We felt confident in our ability to navigate on our own as we both know some spanish and I had studied abroad in Spain. We took a bus from the ship to the main part of the city which cost just a small chunk of change--totally worth it. We bought a map of the city first thing and just walked all over. We walked to La Sagrada Familia and Casa Batlló and it was well worth it. It was a hike however.
Make sure you try the classic sangria and tortilla espanola!