There are a lot of casinos near Cannes- Cannes (3casinos-Palm Beach, Les Princes and La Croisette),, Nice - 2 casinos ( Ruhl and Palais de La Mediterranee), Beaulieu sur mer ( about 10kms from Nice), Antibes, Cagnes and Juan les Pins ( around 10 kms from Nice), Mandelieu and Grasse near Cannes, Menton, Monaco and San Remo ( near Nice). Monte Carlo (4 casinos using the same chips) and San Remo are openned the afternoon. The french casinos only after 8 or 9 pm.
In three or four days you can visit all of them. In 5 days for sure
When I was there I have visited 4 by night.