In the 51st minute, the Cote d'Ivoire forward made it 2-1 against the 10-man Parisians. The game had started in their favour after Thomas Meunier's seventh-minute own goal but Juan Bernat leveled four minutes later.
The left-back was then shown a straight red card just before the interval.
Jonathan Bamba, Gabriel and Jose Fonte scored more goals to condemn PSG to a 5-1 defeat, thus, extending their wait for the Ligue 1 trophy.
The last time a Lille player scored 19 goals was during their successful 2011/12 season when Hazard finished with 20 goals.
Pepe's blistering form this season has seen him linked to a number of top European clubs, and with six league games, he has an excellent chance to surpass the Belgian's mark.