Montpellier overcame Dijon 5-3 as Olivier Giroud grabbed a hat-trick to help them recover from a two-goal deficit while Lyon beat Nancy 3-1 thanks to three first-half goals in an eight-minute spell including a Michel Bastos double.
Lille grabbed a 3-1 comeback win at AJ Auxerre with late goals by Dimitri Payet, substitute Ireneusz Jelen and Mathieu Debuchy as the champions, who started with Joe Cole and Eden Hazard on the bench, moved up one place to fourth on 19 points.
Olympique Marseille drew 0-0 at fifth-placed Toulouse, leaving them 13th and awaiting a second league win this season.
Montpellier trailed to Benjamin Corgnet's double after 11 minutes but the hosts fought back with striker Giroud netting a treble to become the league's top scorer on seven goals.
Montpellier, who have Ligue 1's best attack with 22 goals, looked set to snatch top spot on goals scored but Dijon striker Thomas Guerbert's last-minute strike left PSG top.
BASTOS DOUBLE
Lyon, who welcomed back defender Cris from a long-term injury lay-off, were quick off the mark as Michel Bastos' brace and a goal by Bafetimbi Gomis between the 25th and 32nd minutes gave the seven-times champions a 3-0 lead.
South Korean striker Jung jo-Gook got a consolation with two minutes left as Nancy, who have yet to win this season, stayed bottom of the table on five points.
France playmaker Yoann Gourcuff, back in the Lyon squad after ankle surgery, made his first appearance of the season when he came on as a first-half substitute.
Marseille, who host Arsenal in the Champions League on Wednesday, were once again denied a victory following yet another mediocre performance.
The 2010 Ligue 1 champions, who have won only one league game this season despite having picked up six points from their first two Champions League matches, were industrious at best and had midfielder Charles Kabore sent off in the 58th minute.
But sports director Jose Anigo would not blame his team. "We tried to play and we showed character and solidarity when we were down to 10 men," he told the club's website.
"Arsenal will be another game. It's not the same competition, there's no need to motivate the players."
