Office de Tourisme de Cergy-Pontoise Porte du Vexin
Pontoise
Inscrit à l’inventaire des monuments historiques, ce patrimoine souterrain est unique dans la région.
All year round, every Sunday between 2.30 pm and 4.30 pm.
Closed exceptionally on January 1st and December 25th.
Adult: 8 €
Child: 6 €
Student: 6 €.
Free entry for children < 7 years.