The Cathedral of Saint Etienne in Auxerre is currently Gothic, but has kept the basic features of the original building, including the crypt of the old Romanesque work. The construction of the Church was between the years 1215 and 1550 and was never finished. The South Tower was never constructed because of the slowness of the work and the religious wars and the Revolution. Aside from the cathedral, you can visit the Treasury, which has manuscripts, enamels, paints etc. I recommend to visit the Romanesque crypt dating back to the 11th century, which is what I have highlighted in this cathedral. The crypt under the choir, is a chapel in the apse, and the walls are painted with frescoes dating back to the 12th and 13th centuries. One can see a Christ in Majesty and a set of 4 angels riding around medallions at the ends of the cross of Christ which are on a white horse.
This abbey was established by Queen Clotilde, wife of Clovis, the first Christian king of France and is therefore an important sanctuary. The crypt, which is partly Carolingian style, with graves and monuments dating from the 11th to the 13th Century. The museum houses the ancient abbey of Saint Germain, with an exhibition of Gallo-Roman discoveries in the region, testimony to the long history of Auxerre.