The 30-year-old arrived in Turin earlier this week for a two-day medical and was confirmed as a Juventus player on the Serie A club's website (www.juventus.com).
Matuidi, who has 58 caps, has joined Massimiliano Allegri's Juve side for 20 million euros ($23.48 million), which may rise by up to 10.5 million based on appearances.
The midfielder played 295 times for PSG, scoring 33 goals, after joining from Ligue 1 rivals Saint-Etienne in 2011.
"I'm delighted. I feel really proud to be able to wear this shirt. I'm honoured to wear the Juventus colours," Matuidi said on the club's official Twitter page (@juventusfcen).
"I can't wait to meet my new team mates, get onto the field and start the season with my new team."
(Reporting by Christian Radnedge; editing by Ken Ferris)
