Beaulieu Sur Mer with two children

I just returned from Beaulieu and right outside Hotel Select where I stayed, there is a cute little square. On Friday after school let out, the square was filled with young children laughing, playing ball, and running around having a great time. The parents stood around with wine glasses and welcomed the weekend. Things may be different when you go in July, but this could be a place to check out - the atmosphere was magical!

That square and the restaurants along the street (and the intersecting one) are very nice. I don't think you'll have issues in the summer with being rude (unless you don't say bonjour when entering a shop or other business, but even then, people are used to tourists). Of course, you have the beaches in town and nearby in Villefranche-sur-mer (next stop on the train).

By train, close to the airport is Parc Phoenix (you have to connect to the tram). There is a small zoo, aviary, botanical garden and aviary. Also by train, in Nice you have the large playground in the Promenade du Paillon. There is an area of small jets of water than come up from the group, near the main playground, that is always filled with kids in the summer. In Nice, there is also le Petit Train which gives a tour of the city. In Monaco, there is a large aquarium (Musee Oceanographic) on the top of le Rocher.