PSG miss out on the chance to close the gap on Lille to just one point, after a 1-1 draw with Rennes.
They led 1-0 at the break, after a stoppage time penalty from Neymar, but they struggled in the second half and Rennes had numerous chances in front of goal, forcing Navas to make some excellent saves to deny them.
The hosts eventually got their reward after 70 minutes, when Guirassy powered a header towards goal from a corner and it cannoned off the post and went in.
It got worse for PSG late on, as Kimpembe was shown a straight red on 87 minutes and they played the remainder of the game with 10-men.
PSG are now three points behind the leaders Lille, with just two games remaining, so they need their opponents to slip up in the title race.
They face Reims next time out in Ligue 1, however, they will turn their attentions to the Coupe de France in midweek, as they face Montpellier in the final.
Meanwhile Rennes remain seventh and they travel to Monaco next weekend.