It is the western addition (towards the left, looking at the facade) of the Municipality of Aosta.The structure was built in 1724 (therefore prior to the Municipality); inside this building meetings of the State General Assembly were held, presided by the Bishop and by the Knight Commander. The “Conseil des Commis” would also meet and the archives of the Duchy of Aosta were held inside.Currently the building holds a few municipal offices and some temporary exhibitions.