Ibrahimovic was on target twice in three minutes midway through an entertaining first half after Gignac's solo effort had put the home side ahead in the 17th.
The Swede equalised on 23 minutes with a stunning backheel volley from a corner then put PSG in front two minutes later when he fired a free-kick home from 25 metres.
"We were brave, we gave everything. We deserved to draw," Marseille's midfielder Benoit Cheyou told French channel Canal+.
"Pundits predicted us a 4-0, 5-0 or 6-0 loss. It was important not to lose, were we not able to win this match."
"The draw is logical. We were a bit tired in the second half and we lacked the briskness to break into Marseille's defence," coach Carlo Ancelotti told a news conference.
"Our last two games showed that we still have to improve," he added, referring to PSG's Champions League 1-0 at Porto on Wednesday.
Former Arsenal striker Jeremy Aliadiere's goal ensured Lorient continued their unbeaten run with a 1-1 draw at home to Olympique Lyon, who stay third on 15 points.
Lyon took the lead through France's Bafetimbi Gomis volley in the 23rd minute after a superb collective move.
Lorient levelled the score two minutes after the break when Aliadiere tapped in Benjamin Corgnet's neat pass to take his side up to fourth in the table on 14 points.
Lyon, who suffered their first league loss last weekend, were unlucky to see Gomis's half-volley and then a fine lob from Clement Grenier hit the woodwork early on.
Inspired by Aliadiere and Alain Traore, Lorient reacted but the latter's powerful shot from outside the box struck the woodwork.
