The side from the capital, who did not play last weekend because three of their players were diagnosed with the H1N1 Virus, climbed to 10th in the standings.
PSG, who had not won in the league since August 30, are nine points behind leaders Girondins Bordeaux, 1-0 winners over Monaco on Saturday.
The visitors opened the scoring following a controversial 35th-minute penalty after the referee ruled that Peguy Luyindula had been brought down by keeper Teddy Richert.
Turkey striker Mevlut Erding, back from a lenghty injury layoff, was denied by Richert but midfielder Jeremy Clement followed up to poke the ball home.
Midfielder Clement Chantome doubled the lead when he flicked the ball past Richert eleven minutes into the second half, with Erding, who joined from Sochaux during the off season, adding a third on 74 minutes.
Midfielder Stephane Dalmat pulled one back three minutes from time but Luyindula wrapped it up almost immeidately with a fourth.
Earlier, a goal by Guinea defender Dianbobo Balde inspired Valenciennes to a 3-0 win at Stade Rennes.
The win put Valenciennes, who have the best attack in the French league with 22 goals, up to sixth in the standings with 19 points.
Balde, who spent eight seasons at Celtic before moving to northern France this year, broke the deadlock when he headed home from a free kick shortly before the hour.
Midfielder Fahid Ben Khalfallah made it two 12 minutes from time by beating Nicolas Douchez from close range after a 30-metre run through the Rennes half and striker Gregory Pujol grabbed the third.
Nice beat lowly Le Mans 1-0.
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