Leonardo Jardim's side took a 2-0 lead into half time and, despite Edinson Cavani pulling one back for the visitors, the comeback fell short and Serge Aurier's own goal sealed the result to hand Unai Emery his first defeat in charge of the capital outfit.
It took the hosts just 13 minutes to break the deadlock against the reigning champions when Djibril Sidibe picked out Joao Moutinho in the middle, and the veteran midfielder side-footed his finish past Kevin Trapp from the edge of the area.
One almost became two moments later for Monaco, and again Sidibe was heavily involved down the right flank as he fired in a dangerous delivery that Valere Germain could only steer narrowly wide.
PSG created their first clear chance of the match midway through the first half when Aurier burst forward and slid the ball into the path of Cavani, but the Uruguayan rushed his finish and sent the shot wide of the near post from a good position.
It was Monaco who looked most like scoring again in the opening 45 minutes, though, and Bernardo Silva threatened to double their lead at the end of a quick counter-attack with less than 10 minutes left of the half, only to slice his shot wide.
Fabinho stepped up to the spot kick and made no mistake from 12 yards, picking out the bottom corner to score his second goal of the season and send his side into the break with a two-goal cushion.
PSG responded in the early stages of the second half and saw one Cavani header easily gathered by Danijel Subasic before Layvin Kurzawa missed a glorious chance to continue his remarkable recent goalscoring form when he could only pick out the side-netting from close range after Lucas Moura's low ball had gone all the way across the face of goal.
The visitors did pull one back shortly after the hour mark, though, as Aurier nodded the ball back across goal for Cavani to glance a header past Subasic.
The pressure continued to arrive from the champions, and it took an important intervention from Subasic to keep Monaco ahead when he cut out a dangerous Angel di Maria delivery with Cavani lurking.
It was Monaco who got the game's crucial fourth goal, though, hitting PSG on the counter-attack through Moutinho's pass to Sidibe, who in turn sent a cross into the middle that was deflected past Trapp by Aurier for an own goal.
That proved to be the killer blow as PSG failed to respond in the closing stages, falling to their first Ligue 1 defeat since they last faced Monaco in March.