Les deux soeurs (2006)

Nina is a pretty Parisian girl who's convinced she's 110% gay until the day she surprises Daniella, her girlfriend, making love to a gorgeous blonde. Depressed, she finds refuge in the country, where Oksana, her sister, and her husband live a quite extravagant sexual life. Nina expected country people to be extremely prudish. In fact, she discovres a perfferse, hedonistic world where rich provincial women dressed up in nice lingerie and high heels are indulging in nights of gloriour debauchery with their husbands..