Sailboats, science halls and a metro built entirely of stairs — plan the transport, not the sights.
Jardin du Luxembourg
Push a rented wooden sailboat round the pond, then the puppet theatre, carousel and a fenced playground. Two to ten, all afternoon.
Cité des Enfants
The children's wing of the science museum at La Villette runs timed sessions split by age band. Book ahead; two hours, hands on everything.
Disneyland Paris
Forty minutes east on the RER A, two parks, and prices that reward booking ahead and going midweek outside French school holidays.
Jardin des Plantes
A menagerie, a hothouse and the Grande Galerie de l'Évolution's parade of stuffed animals — the reliable rainy afternoon, from about four.
Stairs versus strollers
Most metro stations have no lift; buses have ramps and are the better bet with wheels. Under-fours travel free, older children at reduced fares.