The hosts now sit two points clear of Borussia Dortmund, who secured a 1-0 victory over Newcastle on Wednesday, claiming the second spot in the group.
Kylian Mbappe set the stage by opening the scoring against Milan in the 32nd minute, unleashing a precise shot into the bottom corner.
In the second half, Randal Kolo Muani and Lee Kang-in netted additional goals, securing a full three points for the French champions.
Mbappe’s stellar form continued, with 13 goals in 13 matches for both PSG and the French national team this season. His goal was the result of a brilliant run by 17-year-old Warren Zaire-Emery, leaving Milan’s keeper Mike Maignan wrong-footed by his strike from the edge of the box.
Despite Luis Enrique’s side’s dominance, their apparent second goal in the 48th minute, courtesy of Ousmane Dembele’s exquisite curling finish, was disallowed by the video assistant referee due to a foul in the build-up.
Five minutes later, PSG secured their second goal after Dembele’s shot was parried by Maignan but was calmly tapped in by Kolo Muani on the rebound.
Maignan’s superb save denied a late strike from Mbappe, as the 2020 finalists finished the match strongly.
The victory was sealed when substitute Lee Kang-in skillfully side-footed the ball into the net following another impressive performance by teenager Zaire-Emery.
Milan continues to struggle in the Champions League this season, residing at the bottom of Group F with two points from their first three matches.
