The champions saw their 26-game unbeaten league run ended on Wednesday night, but there was never any danger of them being beaten on Saturday as they crushed a Sochaux side that has won just one league game all season.
Thiago Silva had PSG 1-0 up at the break and they dominated the second half as goals from Ezequiel Lavezzi and Edinson Cavani, plus a late brace from Zlatan Ibrahimovic, sealed a comfortable win.
Lorient continued their march up the table with Yann Jouffre scoring both goals in a routine 2-0 win over 10-man Rennes on Saturday night.
The visitors paid the price for the early dismissal of Sylvain Armand, with Jouffre scoring from the resulting penalty before adding a second late on to earn Christian Gourcuff's side their fourth successive victory.
The result lifts Lorient above their opponents and into the top half of the table.
Gaetan Charbonnier scored three minutes into injury time to earn Reims a 1-0 win as Nice's terrible run of form continued.
Charbonnier's calm finish at the death kept the hosts firmly in the hunt for a European place, but condemned Nice to a seventh straight league defeat.
Younousse Sankhare denied Valenciennes the victory that would have put them within touching distance of safety when his spectacular second-half strike earned Guingamp an away point.
After just two wins from their opening 16 games, Valenciennes are toiling through the campaign but had a rare win in sight when Tongo Doumbia headed in during the early stages.
They held off Guingamp until the 70th minute when Sankhare produced a sumptuous overhead kick to make it 1-1, a scoreline that stood to the final whistle.
Elsewhere, the clash between St Etienne and Evian was postponed because of a partially frozen pitch.
The game had been scheduled to take place at Stade Geoffroy Guichard but the referee deemed the surface to be unplayable on his pre-match inspection.
A short statement from St Etienne said a new date has yet to be arranged for the fixture.