The official English name of this pretty and compact palace isn't entirely correct as it's roofed with copper and was one of the first such 17th-century buildings in Warsaw to use the metal in this way. It offers two exhibitions: the carpets and woven-arts collection of the Teresa Sahakian Foundation (ground floor), and the apartments of Prince Józef Poniatowski (1st floor).
It's a wing of the Royal Castle and tickets can be purchased from the castle's main ticket office.