The 2018 World Cup winner has signed a five-year contract with the Ligue 1 champions.

"I am very happy to join Paris St-Germain and can't wait to play in my new colours," said Dembele.

"I hope I can continue to grow here and make all the club's fans proud."

Dembele, who also won the Copa del Rey twice, signed a new two-year contract at Barcelona last year.

Barca coach Xavi confirmed earlier this month that Dembele wanted to leave the club.

PSG president Nasser Al-Khelaifi said Dembele, who had a 50m euros release clause in his contract, would be an "important and committed player" for the French side.

He added: "The passion and determination shown by Ousmane as he has signed for PSG is fantastic and perfectly corresponds to the attitude required of all of our players."

Dembele played in the World Cup final in December but a thigh injury meant he missed most of the second half of the season as Barca won the title.

He has been capped 37 times by France, scoring four goals, and is PSG's ninth signing of the summer transfer window.

Meanwhile, France striker Kylian Mbappe and Brazil forward Neymar have been left out of PSG's squad to face Lorient in their opening Ligue 1 game on Saturday.

Mbappe, 24, has been in a contract stand-off with the club amid a desire to join Real Madrid and has not trained with the first-team squad.

PSG's all-time leading goalscorer is refusing to sign a year's extension to his contract, which ends next summer.

Neymar, 31, who reportedly wants to leave the club, is recovering from a viral infection and is training indoors.