While we prefer land tours, the allure of not needing to unpack every two nights had us sign up for this trip. This was our third riverboat cruise. We thought the food was superior to the other cruises (Rhine and Danube - the Danube was our favorite) and we loved the Intercontinental Hotel in Paris (a great location).
In Cannes one of the two excursions is to Nice and Monte Carlo. It is a bit misleading. When we got to Nice we walked to the market to use the bathrooms and were given 20 minutes to do so. Then it was back on the bus to go to Monaco and Monte Carlo. We did not sign up for just a potty break in Nice so we stayed behind, spent the day, and then took the train back to our hotel in Cannes. In talking with people who had continued with this excursion everyone seemed to be disappointed and felt that they never had enough time at any one spot. With only a 15 minute stop in Monte Carlo men were unhappy that there wasn't any time to try their hand at gambling.
I wish this trip stayed in Nice and then there wouldn't be a problem. But, please be aware that if you sign up for this excursion that you shouldn't expect to see Nice. Solution: get off the bus and stay in Nice like we did, taking a train or taxi back to the hotel in Cannes or come in to Nice a day or two early - there is much to see - and then you could also include the Ephrussi Rothschild Villa and its gardens, the village of Eze, or St Paul de Vence.