Belle, there is no general policy for children accomodation at Paris hotels. As the rooms are generally small, it is advisable to book a triple or quadruple room. You can tick family rooms in “refine your search” and sort by “families with young children” in the hotel search engine. We would definitely recommend you three hotels with triple and quadruple rooms that fit your criteria:
Residence Daubenton,
Hotel de Champagne,
Residence Henri IV. Please send us feedback. Enjoy your stay with your children in Paris.