Mary-Kate Olsen Dating Oliver Sarkozy? Getty Images Romance is in the air again for Mary-Kate Olsen. According to Us, the actress-turned-fashion designer is dating Olivier Sarkozy, who is the brother of the former French president, Nicholas Sarkozy. An insider tells Us, "It's true, they're dating, and she's definitely interested in him." There is a 17 year age difference between the Frenchman, who is 42 and Olsen, who is 25. A source suggests she is comfortable with the age-gap. "MK is constantly complaining about boys not being mature enough for her," a friend says. She got the kids out of her system. Now being a businesswoman dominates her time, and she is rarely impressed with guys. The New York Post quotes a source as saying Olsen and Sarkozy are "head over heels." SHOWS: Good Morning America