Lyon, who had not lost in Paris for four years, missed the chance to recover top spot in their see-saw battle with Nice, who had a comfortable 3-1 win over lowly AC Ajaccio on Tuesday.
Nice have 33 points from 18 games -- two ahead of Lyon, En Avant Guingamp, AJ Auxerre and Olympique Marseille with the champions clinging to second place on goal difference.
Guingamp beat Nantes 2-0 in a hard-fought Brittany derby with a powerful header by Didier Drogba on 67 minutes before Hakim Sasi sealed the victory in the dying minutes.
AJ Auxerre began their game at Lille with their morale boosted by the French Olympic Committee, who provisionally handed them back three points for a home win over Sedan that the French Federation had declared void due to a refereeing error.
A win over Lille would have put them level with Nice but they had to settle for a 2-2 draw thanks to a double from their French international Djibril Cisse.
Marseille beat Sochaux with a single goal by Brazilian Fernandao in the 39th minute.
PSG's win moved them up to seventh place and could grant a reprieve to coach Luis Fernandez, who has been the target of stinging criticism from the media and even the club's management over his side's poor performances.
"Of course, it's PSG's duty to play well and to win but people have to understand that one needs serenity and stability to build a great team."
The game, played in pouring rain, was a tense affair with PSG's supporters divided into pro and anti-Fernandez camps.
There was not a single shot at goal in the first 20 minutes but PSG defender Gabriel Heinze eventually broke the deadlock after 38 minutes.
The Argentine slipped behind the defence as Ronaldinho fired in a long-range free kick and he volleyed the ball home from near the penalty spot.
PSG's second goal was also scored by a defender as Morocco's Talal El Karkouri pushed the ball home in the 53rd minute after Lyon goalkeeper Gregory Coupet palmed it into his path following another powerful Ronaldinho free kick.
Stade Rennes coach Vahid Halilodzic sent home Anthony Reveillere and Lamine Diatta a few hours before kickoff at Strasbourg after they spent the night playing video games.
But that did not stop Rennes moving out of the relegation zone by recording a convincing 3-0 win against a side who had won their last six games in a row at their home ground.