Thanks for the replies. Best fun pool for under 5,s was in Corbeil Essonnes near Evry.called stade nautique Gabrielle menut . It's about 25 mins from Milly, full of plastic animals and small slides, 6 inches deep and bath water temp. They do have bigger pools there for older kids. Better than Baltic font pool which is also dull. All pools require tight fitting bathing suits and hats even for babies.
Couple of softplays in Evry but only open weekend and Wednesday and French kids holidays.
If all else fails, there is an ikea in evry, with a great restaurant as long as you avoid those bloody awful meatballs, with the usual play areas in the kids section.
Cheers