Home fans displayed several anti-fascist banners, including one depicting Benito Mussolini, in direct response to the visiting supporters who had earlier given Nazi salutes in Glasgow city centre en route to the stadium.
UEFA so far hasn't specified which banner or chant invoked the charge and the club are unlikely to find out when the punishment is handed down.
• READ MORE - 10 Celtic players who could leave Parkhead in JanuaryCeltic have already had three charges this season and been fined by the association, and could face further punishment after supporters in Rome set off pyrotechnic devices in the away end during the 2-1 win earlier this month.
However, UEFA are still to address disciplinary issues relating to the most recent round of Europa League fixtures.
• READ MORE - Football Manager 2020: the most expensive Celtic players revealedMeanwhile, Fraser Forster has revealed how his last-gasp save against the Serie A side in the 2-1 win at Parkhead made up for 18 months of hell at Southampton.
The goalkeeper said: “Off the back of the previous 18 months, it was an actual moment where you are like ‘that’s why you play football’.
“That moment for me was that. Given the 18 months before, stuff I’d had to deal with, stuff I’d been through, that was probably the first moment when I was like ‘that’s why I’m here, that’s what I’ve missed’."