The St-Pierre-St. Saint-Paul Church was built at the end of the 12th century and the beginning of the 13th century by Jean d'Orbais, one of the architects of Reims Cathedral. …
A beautiful complex, including a hotel, where you can even just enjoy a drink in the castle courtyard. A very pleasant place for a break. Only the champagne, at €12.50 a glass, is a bit overpriced.
This castle was once a fortress. Visits are organized on site (contact beforehand) and several forest acrobatic courses are offered.
More information here: montmort.com