Not far from the Cloister Portal is the little red door which takes its name from the color of its leaves. Opening under the window of the third bay on the north side of the choir, it was erected under the direction of architect Pierre de Montreuil in the second half of the thirteenth century. It connected the cloister, where lived the canons, and the choir of the cathedral to facilitate their access.
This gate was restored in 2012 by the Historical Monuments services DRAC Ile-de-France.
Jean-Pierre Cartier, historian, present it in the video below, subtitled in English.