In response to the desire of several French bishops to be housed in buildings of a strongly secular style, de Cotte designed the palaces of Châlons-sur-Marne (1719-20; not completed), Verdun (1724-35; altered in execution) and Strasbourg (Palais Rohan, planned 1727-8, built 1731-42). Although based on the hôtel type, these buildings were differentiated by de Cotte's incorporation of ceremonial chambers within, and the use of emblematic motifs on the exterior. Part of the building is now occupied by the World Peace Centre.