(US Weekly has a close-up photo of the wardrobe malfunction.)
While watching the race later, Keibler covered the romper with a dark jacket. "So close to all the action!" she tweeted.
She also spent her time on the French Riviera drinking with royalty.
"Heading 2 the palace for cocktails w Prince Albert & Princess Charlene," she wrote Monday.
Notable deaths of 2014 [PHOTOS]
Soviets call Reagan joke 'dangerous' [ARCHIVE]