The former Lille standout has been courted all summer by the Ligue 1 champions and on Wednesday put pen to paper on a five-year deal
Digne, 19, has signed a five-year deal with les Parisiens, having long been linked with a move away from les Dogues, with PSG and Monaco both vying for his signature this summer.
However, Laurent Blanc's men have won the race for the prodigious full-back, who starred for the France Under-20 team which won the World Cup in Turkey earlier in July.
"Playing at Paris Saint-Germain with exceptional players is a childhood dream and a great joy. After becoming a world champion, I had a fantastic summer. I thank the club officials for their confidence," Digne told the club's official website.
PSG chairman Nasser Al-Khelaifi added: "Lucas Digne, a rising star of French football and recent winner of the U20 World Cup, was the subject of transfer interest from a number of major clubs and has chosen Paris Saint-Germain to continue his progression on the European stage.
"We are delighted to welcome this young French player into our squad."
A mainstay of the Lille side last campaign, Digne will be expected to compete with former Barcelona man Maxwell for a place in Blanc's XI.
The left-back, who appeared 44 times for Lille last season, will wear the No.21 shirt for PSG.