A new day means a new bikini for Rihanna, who was spotted earlier this afternoon modeling a bandeau top and white skirt in Saint-Tropez. She took a break from tanning and partying with friends on her yacht to shop in town. Rihanna's not the only Hollywood star enjoying their Summer vacation in France. Leonardo DiCaprio arrived via helicopter yesterday, as did Ludacris. Over the weekend, Rihanna wore a mix-and-match bikini while jet skiing with friends. She's just one of the sexy ladies in the running for this year's PopSugar bikini contest, so be sure to fill out your bikini bracket for a chance to win $500 at Neiman Marcus.