The main horseshoe-shaped courtyard of this mansion is stunning. Porte Clisson bears witness to the fact that it was built in 1375 by the High Constable Olivier de Clisson. In the 18C it was transformed by Pierre-Alexis Delamair into a palace, which houses the Musée des Archives Nationales. You can visit the apartments decorated by Germain Boffrand in a highly imaginative Rococo style. The dazzling princess' chamber and oval salon are utterly enchanting.