The Catalans came into the Camp Nou clash a point adrift of the French champions, but first-half goals from Lionel Messi and Neymar – Barca's scorers in a 3-2 defeat in Paris in September - negated Zlatan Ibrahimovic's earlier effort.
Luis Suarez rounded off the scoring after the interval to subject PSG to their first defeat of the season in all competitions.
Ibrahimovic stunned the home crowd on his return to the club where he spent the 2009-10 campaign - driving home a left-footed effort from 12 yards after 15 minutes.
Barca hit back when Messi met a Suarez cross in the six-yard box four minutes later, and Neymar completed the turnaround before half-time with a delightful curling strike.
PSG's hopes of claiming a point were effectively dashed as Suarez reacted quickest to a Salvatore Sirigu parry 13 minutes from time.
The result sees Barca earn a seeding for the last 16, ensuring they avoid the likes of Chelsea and Bayern Munich, while PSG will be bracing themselves for a tricky draw.
Despite needing a win to top the group, Luis Enrique elected to make five changes to his starting XI, compared to Laurent Blanc's six, but it was Barca who made the brighter start – Messi curling a 20-yard free-kick over the crossbar.
The Barca boss may have been questioning his selection when Ibrahimovic, who had not beaten his former club in five previous attempts, broke the deadlock.
Lucas Moura sent a low cross into the penalty area, where Blaise Matuidi laid the ball off for an unmarked Ibrahimovic to drill home.
PSG's lead was to last just four minutes, though.
A Javier Mascherano ball from deep found Suarez approaching the byline, and the Uruguayan picked out an advancing Messi with a superb first-time cross to tee up his team-mate for a 75th Champions League goal.
Barca continued to live dangerously at the back, and Lucas should have done better when he guided wide from a Matuidi cross, before a completely unmarked Edinson Cavani drew a save from Marc-Andre ter Stegen with a strike from just outside the area.
The hosts began to show glimpses of their attacking talent in the closing stages of the opening half and took the lead through Neymar in the 41st minute – the Brazilian tearing through the PSG half before dispatching a terrific curling effort from 20 yards.
Pedro miscued a cross when Barca looked dangerous at the beginning of the second period, and he was almost made to pay as PSG failed to make the most of a goalmouth scramble at the other end.
Suarez had the ball in the back of the net 10 minutes after the restart, but the whistle had already blown for handball against the former Liverpool man.
Both sides struggled to carve out clear-cut chances thereafter, but Sirigu could only push a first-time shot from Neymar into the path of Suarez in the 77th minute and the striker made no mistake in putting a gloss on the victory with his second Barca goal.
