Paris St-Germain coach Thomas Tuchel said he was surprised to see a video of his players partying two days after they were beaten 2-1 at Bundesliga side Borussia Dortmund.
The loss was in their UEFA Champions League last 16 first leg fixture on Tuesday in Dortmund.
Neymar and Kylian Mbappe were among those attending a late party to celebrate the birthdays of Mauro Icardi, Edinson Cavani and Angel Di Maria.
Tuchel told reporters on Saturday on the eve of their Ligue 1 home game against Girondins de Bordeaux: “I was really surprised yesterday (Friday) afternoon to see that video.
“We talked about it internally and it has to stay within the club.”
PSG lead the standings with 62 points from 25 games, 10 points ahead of second-placed Olympique de Marseille who host Nantes later on Saturday.
The French champions host Borussia Dortmund in the return leg on March 11.