Lucas Paquetá scored against his former Milan teammate Gigio Donnarumma, but PSG beat Lyon thanks to a late goal from former Inter captain Mauro Icardi.
The Brazilian put Lyon ahead after 54 minutes by beating his former teammate at the near post.
PSG star Neymar levelled the score from the spot 12 minutes later and Mauro Icardi gave the Ligue 1 giants all three points with a goal in the stoppages.
Donnarumma started his second game at PSG in the big match at the Parc des Princes.
He joined the Ligue 1 giants in the summer in a free transfer from Milan.
Paquetá moved to Milan in a €38m deal from Flamengo in 2019, brought in by current PSG director Leonardo.
The 22-year-old spent one year and a half at Milan but could only manage one goal in 44 appearances with the Rossoneri.
Lucas Paquetá beats Donnarumma at his near post 👀
— CBS Sports Golazo ⚽️ (@CBSSportsGolazo) September 19, 2021