Under a hotel from 1700 they discovered a medieval castle from 1300. It measured about 42 meters long and 17 meters wide.
It was the castle of John V the Conqueror, Duke of Brittany, in 1381. Dozens of objects "related to the daily life of the castle" were found at the site, including coins, kitchen plates and jewelry.. Renovations in the 18th and 20th centuries turned the building into a hotel, then a law school, and finally government offices built on the original 14th-century castle.