An oval-shaped room, lined by 12 white marble columns, leads into the palace.

The vault has a structured stucco partition in which the coats of arms of the Torlonia family are represented, flanked by allegorical figures of Fame. The walls are lined with a splendid "marmoridea" that imitates "fior di pesco" marble.

The white Carrara marble floors and bardiglio marble have an elaborate partition that matches the design of the ceiling compartments.