Congratulations on booking your first Med cruise. You need to understand that booking private excursions in France and Italy are very expensive (hundreds of Euros) unless you are part of a larger group. Your cruise line will offer multiple excursions in each of your ports. Another option (which we have been doing for over forty years) is to simply do things on our own. But independent touring requires a lot of pre-trip homework and some "travel common sense." All of your ports do lend themselves to independent travel...which can save you hundreds of dollars per day over expensive excursions. My suggestion, as a starter, is to buy Rick Steves new book "Mediterranean Cruise Ports" which does cover your ports. All of these ports offer pretty inexpensive regional train options to exciting places. For example, from Civitavecchia its easy to take a train into Rome, from Livorno you could train to Florence and/or Pisa, and Cannes gives you access to the regional TER train line that connects lots of fascinating places between Cannes and Monte Carlo.