Lorient were 1-0 winners at PSG in the opening round of games last year and they were gifted the perfect start this time around as Maxwell put through his own goal in the second minute from a Kevin Monnet-Paquet cross.
The Brittany club scored a second in first-half injury time as Jeremie Aliadiere eluded a series of PSG tackles before slotting past Nicolas Douchez.
Sweden striker Ibrahimovic pulled one back with a close-range finish in the 63rd minute and tucked away a penalty with two minutes left after Gregory Bourillon was red carded after tripping Blaise Matuidi.
It was a shaky start for Carlo Ancelotti’s men after a summer of major transfer activity which saw Ibrahimovic and Thiago Silva drafted in from AC Milan and Ezequiel Lavezzi brought in from Napoli.
Lyon opened their Ligue 1 campaign with a win after battling past a Rennes side who played more than half of the game with 10 men.
Yoann Gourcuff grabbed the winner for the visitors after 15 minutes and Rennes put themselves at a distinct disadvantage when Jires Kembo-Ekoko was sent off in the 30th minute.
Ludovik Obraniak, Yoan Gouffran and Henri Saivet found the target for Bordeaux in their 3-2 victory over Evian, who had Daniel Wass and Saber Khelifa on the scoresheet for them.
There was another five-goal thriller as Toifilou Maoulida struck twice and Anthony Modeste also scored in Bastia’s 3-2 win away to Sochaux. Sloan Privat and Thierry Doubai netted for the hosts.
A last-minute goal from Benoit Pedretti sealed a 2-1 victory for Lille against St Etienne after Aurelien Chedjou’s opener had been cancelled out by Romain Hamouma, while Yohan Mollo scored the decisive goal as Nancy beat Brest 1-0.
Eduardo netted the winner for ten-man Ajaccio against Nice, while a Rincon own goal saw Troyes open their campaign with a 1-0 defeat at home to Valenciennes.