"Five men in ski masks and police jackets were involved in the robbery about 3 a.m. local time Monday, Reuters reports.
Her purse, two cell phones and 1,000 euros were also taken, police sources tell BFM TV.
Kardashian was gagged and bound at her hands and feet, then handcuffed and held at gunpoint, according to E! News. After the men left with "all her jewelry," Kardashian "broke out of her bindings and got out."
"She begged for them to let her live and [said] she has babies at home. Then they wrapped her mouth in tape and put her in the bathtub," a source told E!. "She thought they were for sure going to kill her."
The men were able to gain access to Kardashian's private apartment after five men threatened the apartment building's concierge with a weapon, handcuffed him and forced him to open the private apartment, says The French Interior Ministry, according to CNN. Two of the men were able to gain entry and a gun was held to her head, according to the Paris prosecutor's office.
Sources tell PEOPLE that Kardashian left her hotel in two vans with a police escort after she gave her statement to investigators.
The convoy blew through red lights in Paris en route to the airport, where a private jet was waiting to take Kardashian back to the U.S.
"She is badly shaken but physically unharmed," her rep tells PEOPLE.
Kardashian has been on a high-profile tour of Paris Fashion Week all week and was joined by husband Kanye West until Wednesday. She was also joined by mom Kris Jenner and sisters Kourtney Kardashian and Kendall Jenner.