The French champions, who welcomed back Neymar after a six-week injury layoff, are ahead of Lille on goal difference after the northerners slumped to a 2-1 home defeat against Nimes earlier on Sunday.
Mbappe put the visitors in front when he fired home from an angle after Marco Verratti's fierce strike had been parried into his path by keeper Anthony Lopes.
Pereira doubled the advantage 17 minutes later with a half volley as PSG stamped their authority on the game with quick passing in midfield, composure at the back and speed up front.
Di Maria added another goal two minutes into the second half with a free kick, before Mbappe, played through by Verratti, slotted the ball past Lopes after outrunning Marcelo in the 52nd minute.
With 84 league goals for PSG and 16 for Monaco, Mbappe is the youngest player to reach the 100-goal milestone in the French top division after Herve Revelli, with Saint=Etienne, in 1969.
Slimani reduced the arrears with an 18-metre shot before Mbappe asked to be substituted.
He walked off the pitch without any apparent pain with 20 minutes left to be replaced by Neymar, who made his first appearance since picking up an adductor muscle injury in a French Cup game against Caen on Feb. 10.
"When I scored the [team's] fourth goal, the first thing I thought about was the fifth," said Mbappe.
"It's an important milestone in my career but I'm still very young and I can improve."
Cornet added another goal for Lyon nine minutes from time with a fine 16-metre attempt that a fully-stretched Keylor Navas could not touch.