Mbappe, who has still not decided whether he will stay at PSG beyond this season, scored twice and had three assists in last weekend's 5-1 rout of Lorient.
He added another assist and won a penalty in this game as he moved to the top of the Ligue 1 goalscoring charts with 20 goals this season.
Mauricio Pochettino's men are now 15 points clear of second-placed Rennes and appear certain to regain the title with only seven games remaining.
Clermont remain in 17th spot, just one point ahead of Saint-Etienne who occupy the relegation play-off place. PSG only have Ligue 1 left to play for this season after being knocked out of the Champions League by Real Madrid, but put in a second straight impressive performance.