Thomas Tuchel's side took the lead through Angel Di Maria, who fired past Anthony Lopes in the seventh minute.
PSG's unbeaten league season came crashing down on Sunday night, with Nabil Fekir netting a second-half victor from the penalty spot.
Argentina worldwide Di Maria opened the scoring after seven minutes, playing a role in a goal for the fourth time in as many games.
Aouar was caught in possession by the lively Draxler, the German racing towards the Lyon penalty area before laying it on a plate for Di Maria to score his fifth of the campaign.
Lyon had the upper hand, though, and PSG were saved by six stops from Alphonse Areola before he failed to handle a Leo Dubois cross, leaving Dembele free to head home from point-blank range in the 33rd minute.
L'avion d'Emiliano Sala retrouvé
Le footballeur argentin venait de quitter le FC Nantes pour s'engager avec le club gallois quand il a disparu en mer. "Nous pourrons opérer demain", a déclaré David Mearns, dirigeant de la société, lors d'un point de presse samedi.
Moussa Dembele, formerly of Fulham and Celtic, shone for the hosts as they inflicted a first league defeat of the season on the reigning champions, by coming from behind to grab a deserved 2-1 victory.
He began his professional career with Lyon, before spells with Marseille and three and a half seasons with Newcastle.
What does it mean? Depay ran the PSG defence ragged throughout the game as he tormented right wing-back Dani Alves and played a pivotal role in their win. And maybe, just maybe, there could be a title race.
Paris Saint-Germain's French forward Kylian Mbappe (C-R) fights for the ball with Lyon's French forward Tanguy NDombele (C-L) and Lyon's French forward Nabil Fekir (L) during the French L1 football match between Olympique Lyonnais (OL) and Paris-Saint Germain (PSG) at Groupama stadium in Decines-Charpieu, near Lyon, on February 3, 2019.
'It feels good to play matches like that.