The French giants made the announcement on social media ahead of a press conference for this evening, when the Newcastle playmaker is expected to talk about becoming a PSG player.
PSG had a £14 million bid rejected for the 28-year-old on Sunday but then returned with a significantly improved offer - reportedly £19m, rising to £20m based on performances - in a successful bid to get their man.
Cabaye has signed a three-and-a-half-year contract with PSG.
The French international has been in the form of his life for Newcastle this season, and Alan Pardew had hoped to keep the player who has been at the heart of his team's good season so far.
But a move to the big-spending French champions, and the lure of Champions League football, convinced Cabaye to return to his homeland two-and-a-half seasons after leaving Lille for Newcastle.
"I could not leave last summer but when I had this opportunity (to join PSG), they stuck to our agreement," Cabaye told reporters.
"I will never forget the two years and a half I spent there and I really want to thank them.
"I'm very, very happy to be here tonight, really proud of getting the chance to take part in PSG's immense project.
"It's hard to say no to PSG for a player. I want to win trophies and this club gives me the opportunity to do so. I did not hesitate at all."
The Magpies are expected to make a move for a replacement in the remaining two days of the transfer window, with Lyon's Clement Grenier their rumoured target.
Meanwhile, PSG president Nasser Al-Khelaifi has ruled out a move for Barcelona star Lionel Messi.
The big-spending French club are believed to be one of the few teams who could afford to sign the 26-year-old Argentinian.
However, Al-Khelafi said there was not a bottomless pit of money for team strengthening.
He told L'Equipe: "If we didn't have any limit, we'd bring in Messi. If Messi isn't coming to Paris, it's because some limits really exist."