Pippa Middleton Parties at Wild Bash Night Before Gun Incident

USMagazine, Monday, April 16, 2012, 11:30am (PDT)

For Pippa Middleton, what happens in Paris doesn't always stay in Paris.

Duchess Kate's famous sister, 27, sparked brand-new global headlines for all the wrong reasons on Monday when it was revealed that she was involved in a disturbing "gun-waving" incident in the City of Lights Saturday.

But that trouble was a universe away on Friday night, when the royal bridesmaid was the biggest VIP in attendance at the lavish, raucous 29th birthday of her fashion mogul friend Arthur de Soultrait (French magazine Gala).

PHOTOS: Pippa's body evolution

Held at a Paris nightclub, Soultrait's over-the-top bash had a Marie Antoinette/Louis XIV theme, with many guests and performers dressing the part -- including one burlesque dancer who popped out of a giant birthday cake to kiss the birthday boy. (Speaking to a reporter in French, Soultrait says Middleton is "a friend" and "supercool."

Middleton herself wore a sexy red 18th-century style dress and gold face paint. Exclusive video from inside the bash (see more photos and details at Gala's website) features Middleton dancing and flirting with male partygoers.

PHOTOS: Wildest royals moments

The next day, she was in the front passenger seat of an Audi convertible when the driver, an as-yet-unidentified male, jokingly waved a gun at photographers. Middleton (and Soultrait, who was in the backseat) could be prosecuted by French authorities for their involvement; the man wielding the gun could face up to seven years behind bars.

PHOTOS: Kate Middleton's body through the years

"Anybody involved in the illegal use of a handgun in public is liable to arrest and interrogation," a police source told Us Weekly.

Go inside the wild party the night before the shocking incident -- watch this video now.

Get more Us! Follow us on Twitter, Friend us on Facebook, Subscribe to Us Weekly