Middleton, 28, was in an Audi convertible with the driver, pal Arthur de Soultrait, and another man during the incident on Sunday, in which a witness filed a complaint to local authorities.
An insider told the UK Sun: “If the evidence points to her involvement, she will be prosecuted. Anybody involved in the illegal use of a handgun in public is liable to arrest and interrogation.”
If it is determined the gun is real, the driver could face seven years behind bars; if fake, it would be a two-year sentence.
The newspaper’s royal editor Duncan Larcombe told Good Morning America on Monday, “We’re told [the French photographer the man allegedly aimed the gun at] isn’t ruling anything out yet.”
Larcombe said the other men in the car with Pippa are French socialites.
“Pippa is a party girl,” he told the show. “She mixes now in very high society and they don’t come very higher than this group of French aristocratic sons.”