Celtic could face punishment from UEFA after a pitch invasion by a fan, highlighted by an apparent attempted kick at Paris St Germain's Kylian Mbappe during their 5-0 home Champions League defeat.
The fan ran towards Mbappe shortly after PSG's third goal in Tuesday's first half before being caught by stewards and taken off.
Celtic manager Brendan Rodgers expressed his disappointment, although he praised the reaction of most of the sellout crowd who loudly booed the invader.
"It was disappointing at any ground, at any club, a supporter getting on the pitch like that," he said.
"It was bitterly disappointing and I am sure the club will deal with whoever that supporter was. It shouldn't be anything that we should see.
"I think the stewards dealt with it at the time and I am sure the club will deal with it."
Celtic were fined £20,000 ($A33,144) by UEFA in July after an "illicit banner" was displayed in the crowd against Irish club Linfield in a Champions League qualifying match.