I would recommend the Four Seasons -- the location suits your needs, the staff are good at handling kids, there is a good gym and pool in the hotel (only open to hotel guests), Playstations in the rooms, connecting rooms and suites and are of very generous size. The service at the George V is friendlier and more "North American" than the other hotels, which, is IMHO welcome in Europe at times.

I find the Bristol to be pretentious and a little stiff in atmosphere for the kids. The Chef Concierge at the George V, Roderick, is the best Concierge in the city and is also the most humble and friendly man one can meet.

Should you decide on the George V I do not think you will be disappointed. However, in Paris, the luxury hotels you mention are NOT cheap. You might find family packages through the hotels directly (Four Seasons) or through Leading Hotels of the World (for the Bristol, Meurice, Ritz, Crillon, and Plaza Athenee).

I hope you enjoy your visit to Paris!! Please report back with your experiences.