I figured out why the Hiltons are involved with the brand. The other co-founder is a man named Lucien Georges Lallouz. He is apparently behind the licensing deals for Paris’s brands and has done some work with Kathy too. I know Kathy used to have perfume and skincare line.

From his LinkedIn:

Paris Hilton was not known for anything in 2002 when Lucien created and licensed her brand for Fragrances, Luxury products, including small leather goods, Eyewear, Cosmetics, Footwear and launched Paris Hilton Watches with Tourneau NYC priced from $100 to $200K, all reaching billions of dollars in retail sales worldwide. Paris's success, spawned the Kardashians who thanks to Paris' brand awareness, became an American cottage industry also worth billions.

Licensing rights of various consumer products for the Picasso Estate, Modern Art Cafe & Art Galleries globally, Charles Jourdan, Pierre Balmain, Guess?, Maria Sharapova, Jesica Simpson, Kathy Hilton, Julio Iglesias, Phantom of the Opera, Ted Turner's Gone with the Wind and other celebs, including the M&A of Perry Ellis fragrance brand worth $140 million.