Paris Saint-Germain fans have promised to clean up their act after being hammered for ignoring social distancing rules.
The club's Ultras insist they will behave at Tuesday's clash with Celtic after being forced into a grovelling apology.
Supporters sparked fury in France after they ignored coronavirus advice from their own club about sitting apart during their 7-0 friendly win against Waasland-Beveren last week.
Despite only 5,000 fans being in the Parc des Princes, the PSG fans sat together and that prompted Patrick Wolff, the president of France's National Association of Professional Sports Leagues, to state: "The PSG Ultras shot themselves in the foot and at the same time shot in the foot of all French professional sport.
"Everyone must be responsible. I have a great feeling of sadness after what happened at the Parc des Princes.
"This was a test after we have been working for weeks to introduce this next phase and because of their selfish actions, they could have put jobs in jeopardy on an economic level if a ban is reinstated."
And PSG Ultras leader Romain Mabille has promised there will be no repeat against Neil Lennon 's side, with the capacity again limited to 5,000.
He said: "We underestimated our enthusiasm and we managed it very badly.
"We were irresponsible and against Celtic, we will try to show that we are able to behave responsibly, even if the atmosphere suffers because of it."
