The 18 year-old has committed to a contract to 2030 and joins PSG for €8.5m.
PSG agreed to pay higher than Dro's €6m buyout clause in order to ease the tension with Barca over their swoop.
The midfielder joined Barca at the age of 14 to play for the Under-16 B team from Val Miñor and this was his fourth season with the Blaugrana. His rise has been meteoric.
This season, Dro made his debut in La Liga and the Champions League, starting in both competitions. In the league, he debuted in the first-round match against Real Sociedad and in the top continental tournament, against Olympiacos.
His last minutes as a Barça player were the 16' he played against Atlético Madrid.
Upon signing, Dro said this morning: "I am very happy and very proud to join Paris Saint-Germain. It is a very proud moment for me and my family.
"PSG is a huge club that I have followed since I was a child, where great legends have made history. Today I am very eager and motivated to play and give my all for this shirt."