The Uruguay striker, who wasted a handful of chances in the French champions’ 1-1 home draw against Arsenal in the Champions League on Tuesday, found the back of the net four times before the break in a one-sided encounter.
Monaco, Girondins de Bordeaux and Nice, among others, could take over at the top depending on Saturday’s results.
Cavani opened the scoring after 12 minutes when he latched onto a Maxwell cross from the left and doubled the tally from the penalty spot after Syam Ben Youssef fouled Lucas in the box.
Maxwell again set up Cavani for the third, the forward tapping in from a cross at the near post seven minutes from the break. Cavani added a fourth on the stroke of halftime, poking the ball home from Thomas Meunier’s cross.
Forward Jean-Kevin Augustin added a sixth, converting Adrien Radiot’s assist 11 minutes from time.
Monaco take on Stade Rennais and Bordeaux host Angers on Saturday.