Bono & The Edge have been making the scene in St. Tropez, France over the past few days, and that included an impromptu singing performance on Sunday from their table at Club 55. It looks like they're performing with young singer/songwriter Alex Karlsson and/or his band. (He's the one who tweeted about it and uploaded the video below to YouTube.) Anyway, it's a singalong of The Beatles' "Help" and here's a bit of how it sounded.
There are also some more photos of Bono and Edge (but not the singalong) on Zimbio.
UPDATE: @U2 reader Alex points us to this Facebook photo from Phly Boyz, the band that performed with Bono & The Edge.