PSG had found it difficult to break the deadlock, but managed to find their first goal through a Kylian Mbappe strike, before Brazilian superstar Neymar had added a second with a deflected shot.
The hosts seemed to be crusing to another win, but that was out in doubt when the referee awarded a penalty in the 91st minute.
Defender Thilo Kehrer was judged to have handled the ball in his own box, with Nicholas Pepe the man to step up for the resulting spot kick.
The Ivorian international strode up to the ball assuredly and smashed it in to the top-left corner of the net, giving Gianluigi Buffon no chance of getting a hand to it.