Vitinha put PSG ahead at the Stade de la Mosson and Mbappe doubled their advantage midway through the first half, only for an Arnaud Nordin header and a Teji Savanier penalty to bring Montpellier back level at the interval. However, a marvellous Mbappe goal restored PSG's lead shortly after the break and Lee Kang-in made it 4-2 before the France captain completed his hat-trick.
Nuno Mendes put the seal on the victory late on, as Luis Enrique's side ended a run of three successive draws in Ligue 1 and extended an unbeaten domestic record stretching back to September. A 1-1 draw for nearest challengers Brest against Lille earlier on Sunday means the Parisians are now 12 points ahead at the Ligue 1 summit with only eight games left, and a 10th title in 12 seasons is an inevitability.