Nice, the capital of the Côte d'Azur, is not 'nice' - what an insult! Nice is a sparky, sexy city, with a gritty underside that keeps it grounded. If Nice were a person, it would wear designer cocktail dresses with old army boots, cause lots of trouble and be livid about that insipid adjective.
Nice's beaches are pebbly. On the other hand there are a lot of them, and most are free, warm and clean as a whistle. The city itself is brash and bold (there's no such thing as being too old to wear a bikini) and enormously popular, so if you're looking for a place of serenity and Zen-like peace… move on.