Celtic have been hit with a €16,000 fine from the UEFA's Control, Ethics and Disciplinary Body for setting off fireworks in the Stadio Olimpico.
Lazio have also been found guilty and fined €2,500 for setting off fireworks and €6,750 for throwing of objects.
The levies come after a highly contentious double-header where tensions had been raised between both sets of supporters.
Lazio ultras were filmed in Glasgow city centre making fascist salutes before Celtic fans raised banners stating 'f*** Lazio' in Italian and insulting wartime fascist Italian leader Benito Mussolini.
The Hoops were fined £12,900 for these contravention and singing 'illicit chants' at Parkhead.
It represents the 20th time Celtic have had to stump-up cash to UEFA since 2007 and their fourth charge in Europe this season.
The Italian club were also been fined £8,600 for "illicit chants" during the 24 October meeting.
Celtic won both ties 2-1, topping Europa League Group E and making it nearly impossible for the Roman giants to qualify.
