Since the 16th century, the Royal Castle has been not only the residence of the monarch, but also the meeting place of the Parliament of the Republic of Poland. The Parliament Chambers are located in the west wing of the Castle on the first floor.

New Deputy Chamber – until 1792, the lower house of the Polish Parliament held sessions in this hall. The deputies sat on benches arranged in an amphitheater, with an armchair for the marshal in the middle. The current decoration consists of gilded stucco in the form of panoplies and allegorical supraports. On the walls there are portraits of monarchs from the Saxon dynasty and their wives, as well as hetmans from the first half of the 18th century. We can admire Saxon furniture and porcelain from the collections of Augustus III. On one of the walls there is an impressive painting depicting the maneuvers of Polish, Saxon and Lithuanian troops in Czerniaków near Warsaw in 1732. 

The Senators' Hall is one of the most magnificent rooms in the Castle. The Constitution was adopted on May 3, 1791. After the fall of the November Uprising, the decoration of the hall was destroyed. Currently, it has been rebuilt based on drawings showing the appearance of this room before the destruction. The royal armchair and fragments of the decoration of the back room and the throne canopy are original. The decoration of the throne was reconstructed according to the design of Andrzej Grzybowski, and the painting decoration of the room was made by Andrzej Bertrandt. The arrangement of armchairs and chairs for senators and ministers was recreated strictly in accordance with the applicable ceremonial of the Polish Parliament.