Dear Julie,
Your chosen site is in the Melun/Fontainebleau area of ILE-DE-FRANCE - which is the department that surround s Paris.
I have the latest copy of "Camping & Caravaning" which is the French version of Practical Caravan (only much better) and it has very good lists of sites of sites near to Paris. However the site you have chosen isn't considered; probably because is it some way from Paris.
I've looked at its website which gives a good indication of its standard - i.e. the Dutch go there and that's always a good recommendation in my book as they have loads of inspectors that visit camps and give then ratings from their two main organisations.
To get to and from Disney is 49.78 miles each way and looking at the roads you would have to take it has to be at least 1 plus hours drive each way.
On the area of Fontainebleau and Melun it is highly rated in French circles seen as a good place to live and bring up children.
Let me know if you need anymore info
Kindest regards
Monkeys Husband