Hakimi has signed a five-year contract with the Parc des Princes outfit and leaves Inter Milan after just a single season in Italy.
The 22-year-old joined Inter from Real Madrid last season following two seasons on loan at Borussia Dortmund and was instrumental in the Nerazzurri winning a first Serie A title in 11 years under Antonio Conte.
Hakimi made 37 Serie A appearances and scored seven goals from right wing-back.
He becomes PSG’s second summer signing following the free transfer signing of Georginio Wijnaldum from Liverpool. Mauricio Pochettino’s side could also add Gianluigi Donnarumma, Sergio Ramos and Danilo Pereira to their ranks in the coming days.
"I feel a great sense of pride," Hakimi, who has 36 caps for the Morocco national team, said via PSG's website.
"After Spain, Germany and Italy, Paris Saint-Germain offers me the chance to discover a new championship with one of the most prestigious clubs in the world. I can't wait to meet my new team-mates, the fans and experience the incredible colour and passion inside the Parc des Princes.
"I share the same big ambitions as the coaching staff and my team-mates and will do everything I can to deliver what is expected of me."
Chairman Nasser Al-Khelaifi added: "We are delighted to welcome Achraf Hakimi to Paris Saint-Germain. This calibre of signing shows the level of our ambitions – we continue to build something very special.
"Achraf may only be 22 years old and has already established himself as one of the most talented full-backs in world football – these are the standards we set at the club. I know Achraf will have a fantastic career with us and the whole club wishes him every success in our colours."
