Sardinia is full of sunshine and it is accessible from Nice by ferry. Take a look at this link. http://www.corsica-ferries.co.uk/travel/sardinia.html
Browse the internet rather than listen to me. http://www.italia.it/en/discover-italy/sardinia.html
You will quickly find a paradise whether you want walking, climbing, sandy beaches, fabulous food, sailing and beautiful island life.
You don’t even need to take a tent with some camp sites.
Please click on this image below to see much more.