The armed men robbed Kardashian at gunpoint at around 3 a.m. (0100 GMT), but no one was hurt, the source told Reuters.
The attack happened in a discreet luxury residence used by celebrities and wealthy individuals behind the French capital's Madeleine church.
Kardashian has stayed there at least once before, in 2014, before her marriage to rapper Kanye West.
West was said to have abruptly ended a performance in New York after learning his wife had been attacked
Kanye just cut his #themeadowsnyc set short, citing a "family emergency." pic.twitter.com/Yg6VQC5ieQ— Genius (@Genius) October 3, 2016