Since June 1999, the fore-nave of the Abbey church has been open to the public. Archaeological digs conducted over a ten-year period have unearthed vestiges (stonework and sarcophaguses) from the 6th, 7th and 9th centuries.
Worth seeing are the chapter room (12th century), storeroom (14th century) or cloister (17th century), and as you leave the Abbey, admire Saint-Jean Tower (12th century) and its impressive stone steeple with eight convex sides. The crypt has some of the most ancient mural paintings in France, and houses the tomb of the bishops of Auxerre.