Marvel at the size of Pontoise Cathedral. Stay for a service if you can or simply take a seat and enjoy a break from the outside world.
If you love hearing the word "free" as much as most people do, you'll be happy to know this principal church is exactly that. Pontoise Cathedral is located in Centre-Ville. If you want to keep your travel schedule full while you're in the area, also stop by Abbaye de Maubuisson, Castle of Auvers and Cergy Pontoise Leisure Island.