The France midfielder has penned a three-and-a-half-year contract at the Parc des Princes.
The Ligue 1 champions said in a statement: "Paris Saint-Germain is delighted to announce the transfer of Yohan Cabaye to the capital club from Newcastle United until June 2017. He will wear the number four jersey."
PSG had a £14million bid for Cabaye rejected by the Magpies on Sunday but the Ligue 1 champions have now secured the services of the 28-year-old.
Neither club have revealed the price final tag for Cabaye - with Newcastle
announcing the sale for "an undisclosed fee'' on their website.
Cabaye said of his move: "I was won over by the ambitious project at Paris St Germain and I can't wait to join this exceptional squad and help the team reach its objectives in France and in Europe.''
Cabaye will link up with the likes of Zlatan Ibrahimovic, Edinson Cavani and
Thiago Silva at big-spending PSG, who last season were crowned French champions for the first time since 1994.
Managed by former France coach Laurent Blanc, PSG are also on course to retain their title this term as they currently boast a three-point lead over
second-placed Monaco, with Lille 10 points back in third.
PSG are also through to last 16 of the Champions League, where they will face Bayer Leverkusen in the first leg next month, and in the Coupe de la Ligue semi-finals.
Club president Nasser Al Khelaifi said they had beaten a number of top sides to Cabaye's signature.
He said: "Wanted by a number of prestigious clubs, the new Parisian midfielder has chosen to join Paris St Germain.
"The transfer of Yohan Cabaye is further proof of the club's capacity to attract the best French and overseas players.
"We are exceptionally delighted to welcome him to the Paris St Germain family to help in its upcoming challenges in the second half of the season.''
Cabaye joined Newcastle from Lille for £4.3million in June 2011 and soon established himself as a key player for the Magpies and a fans favourite on Tyneside with his energetic box-to-box probing and long-range shooting ability.
In his first season he flourished alongside Cheick Tiote in midfield and helped Alan Pardew's men to a fifth-placed finish - the club's first top-10 finish in the Premier League since 2004 - which earned them a place in the Europa League.
Last season Newcastle only managed to finish 16th but, despite that, Cabaye was still the subject of interest from Arsenal in the summer, with the Magpies turning down a "derisory" bid believed to be in the region of £10million from the Gunners.
News of that offer became public just prior to Newcastle's 2013/14 season opener at Manchester City and Pardew decided Cabaye was not in the right frame of mind to play at the Etihad Stadium and sent him back to the north-east.
Cabaye also missed the subsequent matches against West Ham and Morecambe as speculation about his future continued, with PSG reportedly trailing the midfielder along with Arsenal.
Cabaye returned to the team for the match against Fulham, appearing as a second-half substitute in the 1-0 win as Newcastle earned their first league victory of the season, before being restored to the starting line-up for the subsequent triumph at Aston Villa.
Following his appearance against Villa, Cabaye apologised to Newcastle fans for the confusion over his future at the start of the season and insisted he was still happy at the club.
In total, Cabaye made 79 Premier League appearances for Newcastle, scoring 17 goals.
A Newcastle statement read: "Yohan leaves the club after two-and-a-half seasons at St. James' Park.
"Newcastle United have benefited significantly from Yohan's talents since his arrival from Lille in the summer of 2011, and the player has likewise benefited, developing hugely during his time on Tyneside.
"The club wanted to keep him but the lure of Champions League football and the prospect of being involved in the sporting project at PSG was an opportunity that Yohan made very clear to us he wanted to take.
"Yohan leaves the club with our best wishes for his future at PSG and, hopefully, as part of the French national squad for this summer's World Cup."