From the text:
Courtesans is a Roleplaying Game. Not necessarily that sort of 'roleplaying game', but if that's what floats your boat don't let me stop you.
Anyway Courtesans casts you, the Players, as Ladies of the Demi Monde, the half world below the respectability of society, who are scandalously free with their favours. Well not free. They have a price, be it money or something more ephemeral. Though you share a house with the Characters of the other Players you are in competition with them. Let the backstabbing and the bitchiness commence!