A really fun place. Wave pool, river run, whirlpool, huge slides, indoor and outdoor swimming pools.
Address: 4, rue Louis Armand, Paris, 75015. Métro: Balard on line 8 or Porte de Versailles on line 12 Buses: 39, 42, 126, 169, PC, stop at Balard. Parking for 900 cars.
It's not cheap - about €20 to €25 for adults, about €10 for kids.