Sloggi is well known for plastering underwear clad derrières on billboards throughout Europe. But during the Tour de France the ads become a bit more, shall we say, topical. Apparently the bicycling beauties first appeared in England during the 2002 Tour and have emerged for this year's prologue as well.
You can find more of the back story on both Quickrelease.tv and Velogal, but I know that you want to see more so to that end I must lead you to the b-sides my friends.