Cagnes-sur-Mer is a French Riviera town near Nice that is in the Alpes-Maritimes department, in the Provence-Alpes-Côte d'Azur region, in s…Cagnes-sur-Mer is a French Riviera town near Nice that is in the Alpes-Maritimes department, in the Provence-Alpes-Côte d'Azur region, in southeastern France.