The Princess and the Whore(1996)

Original title: La Princesse et la pute

As a consequence of a stupid bet, two leaders of the Principality of San Cito decide to swap sweet and pure Princess Sofia with Helga, the queen of sex, a nymphomaniac prostitute. Thrown out of the palace, romantic Sofia becomes a guest of the Blue Pussy, a luxury whorehouse, where she is exposed to the sexual fantasies of men who submit her to their luscious will. On the other side Helga the whore who has a hard time understanding good manner is suffering of her present poor sexual life, due to the etiquette, so she decides to make a pilgrimage to the Blue Pussy where she meets ex Princess Sofia.