Sofia Coppola has never directed a historical period drama before, but her biopic ''Marie-Antoinette'' should be a piece of cake. After all, the casting will be something of a family affair. Kirsten Dunst, whom Coppola killed off in her directing debut, ''The Virgin Suicides,'' will lose her head as the guillotined queen. Playing France's King Louis XVI, Marie's husband, will be Coppola's cousin, ''Rushmore'''s Jason Schwartzman. ''I've always loved the story of Marie-Antoinette and the decadence of Versailles on the brink of revolution,'' Coppola said in a statement, "and the fact she was just a teenager when circumstances forced her to play a significant role in history.'' The Oscar-winning ''Lost in Translation'' screenwriter will write and direct the film, which will shoot in France next February.