For Franck Haise’s team, Lois Openda scored one goal and assisted on another.
Lionel Messi, who is still recovering from the World Cup, and Neymar, who was suspended after receiving a red card on Wednesday, were both absent for PSG.
Przemyslaw Frankowski gave the hosts the lead after five minutes when he volleyed into an open goal off Gianluigi Donnarumma of Italy.
Hugo Ekitike soon restored PSG’s advantage, but Openda gave Lens the lead once more in the 28th minute by eluding defender Marquinhos and firing past Donnarumma into the bottom corner.
Despite Kylian Mbappe playing the entire game, Alexis Claude-Maurice added a third two minutes into the second half, and the team from northern France managed to hold on for a significant victory.
On their first game back after the World Cup, Lens drew with Nice last week, but since then, they’ve won six of their past eight league games and all nine of their home games this year.
Ten days after losing to Real Madrid in the Champions League, PSG suffered their most recent loss, a 3-0 loss to Monaco on March 20.