Fascination (1979)

1905. Marc, a thief, escapes from four other thieves. He is planning on heading to London with a bag of gold coins, but must take refuge from his pursuers. He discovers a château isolated in the mountains looked after by two chambermaids, Elizabeth and Eva, who are awaiting the arrival of the Marchioness and her servants. The women turn out to be part of a cult of lesbian vampires in search of male blood. After the necessary temptations, the thief succumbs and falls for one of the women, which ultimately results in a (lesbian) orgy of swarming blood-drinking vampires.