Pippa Middleton attended a wild Paris party featuring dwarfs and strippers hours before her friend's infamous toy gun prank, The Sun reports.

The Duchess of Cambridge's younger sister let her hair down at the raunchy costume bash held in a city theater.

The party, which also included kinky masks, bondage outfits and a woman fire-eater, making sparks fly with a power tool, was held Saturday to mark the 30th birthday of aristocrat and fashion leader Arthur de Soultrait.

It was staged the evening before Middleton, 27, was plunged into a storm which led to fears she would face questions by French police.

She was pictured riding as a passenger in a convertible Audi and laughing while the driver clearly aimed what looked like a semi-automatic pistol at a photographer behind the vehicle.

Police were studying the pictures after receiving a formal complaint about the incident, which happened as Middleton was being driven to the city's Gare du Nord station to catch a Eurostar train to London.

On Monday, her BMW was parked in front of her parents' $2.4 million home in Bucklebury, southern England.

A member of staff who answered the door would not say where the family was. A police car was seen heading up to the property later.

The driver in the Paris incident, who was not identified, was keeping a "low profile" Monday.

Party host de Soultrait, who was in the back of the Audi with his brother, was reported to be "mortified."

France is on heightened security alert after a string of handgun murders, including a massacre in Toulouse.