A few alterations from Thomas Tuchel's saw Kylian Mbappe making a return alongside Moise Kean, with a fit-again Neymar Junior reduced to the bench.
PSG bagged opening goal five minutes to the half-hour mark off a deft finish inside the box from Mbappe following Angel Di Maria's ball through the middle.
The 2018 FIFA World Cup winner made it two goals in the final seven minutes of the first half when he beat Vito Mannone from the penalty spot after Youssouf Fofana handled Rafinha's ball.
Mbappe appeared to have nabbed a hat-trick minutes later after lobbing Mannone off a ball from Abdou Diallo, but it was ruled out by the Video Assistant Referee (VAR) following an offside.
Two substitutions from Monaco at halftime followed with Cesc Fabregas and Caio Henrique introduced for Willem Geubbels and Fode Ballo-Toure respectively.
These introductions paid dividends 52 minutes in when Kevin Volland made no mistake with a close-range finish from excellent build-up play.
Neymar appeared from the substitutes' bench in place of Di Maria eight minutes later in place of Di Maria, as the visiting side looked to wrap up the contest.
However, the home side went on to grab an equaliser midway through the second half with Volland finding a brace after helping Fabregas' sliding pass into an empty net.
The turnaround was complete for Monaco six minutes from full-time when Fabregas dispatched a penalty kick after Volland went down under Diallo's challenge, which also resulted in a red card.
PSG went all out for the equaliser in the last seconds of the match, but Monaco held out for the win to move within four points of Thomas Tuchel's men.