Champions PSG lost 2-1 at Strasbourg on Saturday (Sunday AEST).
With the match coming between the two legs of the Champions League semi-final against Arsenal, PSG coach Luis Enrique rotated his team. Only Joao Neves was retained in the starting XI.
PSG started with four players born in 2006 or later: Warren Zaire-Emery, Senny Mayulu, Axel Tape and Ibrahim Mbaye.
"I'm very proud of the young players, they showed what they're capable of," Enrique said.
"We played a very good match but didn't get the result we wanted. Now we need to recover and concentrate on Wednesday's game."
Star striker Ousmane Dembele, who picked up a light hamstring injury in the 1-0 win in London, was rested ahead of this week's game against the Gunners at the Parc des Princes. Bradley Barcola, Mbaye and Goncalo Ramos started up front.
Strasbourg took the lead from a corner. Mamadou Sarr's glanced header was clumsily diverted in by PSG defender Lucas Hernandez. It was Strasbourg's ninth goal from a corner, the highest tally in the French top flight.
PSG were punished again just before halftime when Felix Lemarechal curled in a superb strike from outside the box.
Barcola pulled one back just after the interval. He collected the ball inside PSG's half, went on a 50-metre run into the area and finished the impressive solo effort from close range with remarkable composure.
The result extended Strasbourg's unbeaten run to 12 matches and lifted the team to fifth in the standings. Strasbourg have collected more points since the start of the year 0 40 - than PSG.
PSG suffered consecutive Ligue 1 losses for the first time in more than two years. The team's bid to go unbeaten in Ligue 1 was ruined last month when they lost 3-1 to Nice.
Monaco striker Folarin Balogun scored his first Ligue 1 goal this year following shoulder surgery, as struggling Saint-Etienne were beaten 3-1.
The US forward was picked out by Maghnes Akliouche and beat the offside trap to seal Monaco's win from the edge of the box.
Akliouche put Monaco ahead after just two minutes. Zuriko Davitashvili levelled for Saint-Etienne in the second half, three minutes before Moatasem Al Musrati put the visitors back in control.
Monaco moved into second place, level on points with Marseille, who have one match in hand and play at Lille on Sunday. Saint-Etienne remained in the relegation zone.
Balogun returned to competition in March after undergoing surgery in December on a dislocated shoulder.
Goals from Yann Gboho and Aron Donnum helped Toulouse to their first home win since mid-December.
Toulouse defeated Rennes 2-1 to end a seven-match winless streak and move level on points with their 11th-placed rivals.