Ibrahimovic, PSG's major summer signing from AC Milan, equalized from the penalty spot in the 90th minute after pulling a goal back midway through the second half with a clinical finish.
PSG, which spent $185 million on players in the off-season in addition to a $123 million outlay last season, left to jeers at halftime, after an own goal from Brazilian defender Maxwell and a well-taken goal from forward Jeremie Aliadiere put the visitors 2-0 up.
Bordeaux and Lille both enjoyed away wins on Saturday, while defending champion Montpellier drew 1-1 at home to Toulouse on Friday.
A last-minute winner from midfielder Benoit Pedretti gave Lille a 2-1 win at Saint-Etienne, while Ludovic Obraniak, Yoan Gouffran and Henri Saivet were on target in Bordeaux's 3-2 win at Evian.
In Saturday's other results, it was: Nancy 1, Brest 0; Nice 0, Ajaccio 1; Rennes 0, Lyon 1; Sochaux 2, Bastia 3, and Troyes 0, Valenciennes 1.
But all eyes were on Parc des Princes for PSG's first game of a new season that promises to erase the pain of finishing second to Montpellier in the last campaign.
Ibrahimovic headed wide with the goal at his mercy in the 85th minute, but the imposing Swede — last season's top scorer in Serie A with 28 goals — made amends by dispatching the late spot-kick after substitute Blaise Matuidi was hacked down as he ran through.
PSG coach Carlo Ancelotti had two other new signings in his starting lineup, with the 19-year-old Marco Verratti in central midfield and Ezequiel Lavezzi on the left wing. Jeremy Menez started on the right wing, with Brazilian Nene — last season's joint-top scorer with 21 league goals — left on the bench.
Menez saw his snapshot saved by Fabien Audard in the third minute and a minute later, Lorient scored from its first attack when Kevin Monnet-Paquet crossed from the left and Maxwell attempted to intercept the cross, but instead poked the ball into his own net.
Menez's cross from the left just avoided Lavezzi's outstretched leg, Ibrahimovic forced Audard into a save with a downward header, and Alex headed wide of an open net as PSG pressed for an equalizer.
Audard denied Lavezzi with a reflex save in the 36th and Ibrahimovic was thwarted by a brilliant block from defender Jacques-Alaixys Romao just as he was about to stroke the ball home.
Just 45 minutes into his debut, Ibrahimovic started to show his first signs of frustration as an aimless long ball sailed over his head, and he gesticulated angrily with his hands.
Lorient, having had another goal ruled out for offside, caught PSG napping on the stroke of halftime when Aliadiere cut inside from the left, left centre backs Alex and Mamadou Sakho in his wake, and planted a low shot past goalie Nicolas Douchez.
Shortly after the restart, Ibrahimovic set up Lavezzi for a chance, but Audard kept out his close-range effort, and then Ibrahimovic hit the crossbar with a half-volley after Lavezzi picked him out near the penalty spot.
The tall striker had better luck with his next effort, expertly controlling a high cross on his chest, holding off a defender and then slotting the ball into the corner to make it 2-1 in the 64th.
Elsewhere, former France playmaker Yoann Gourcuff signalled his return to form with Lyon's winner; Brazilian forward Eduardo got Ajaccio's goal at Nice; winger Yohan Mollo scored an injury-time winner for Nancy, and veteran forward Toifilou Maoulida scored twice to give newly promoted Bastia a morale-boosting win.
In Sunday's game, Reims is at home to Marseille.