Manchester City have been charged by UEFA after fireworks were set off during their 1-0 Champions League quarter-final second-leg win over Paris St Germain at the Etihad Stadium on Tuesday night.
The charge tempers celebrations after City advanced to a first Champions League semi-final with a 3-2 aggregate win over PSG.
A statement from UEFA read: "Disciplinary proceedings have been opened following the UEFA Champions League second-leg quarter final between Manchester City FC and Paris St Germain (1-0) played on April 12 in England.
"Charges against Manchester City FC: - Setting off of fireworks - Art. 16 (2) of the UEFA Disciplinary Regulations.
"This case will be dealt with by the UEFA Control, Ethics and Disciplinary Body on May 19."
UEFA considers it the club's responsibility to police the use of fireworks, or flares, by supporters.
City in November avoided disciplinary action for their fans booing the Champions League anthem.
UEFA's disciplinary body reviewed the case after the booing was reported by the match delegate following October's home win over Sevilla and decided not to take any action.
City's fans have regularly booed the anthem, which is taken from Handel's Zadok the Priest, to express their unhappiness with UEFA.
Issues that have angered fans include financial fair play sanctions and last season a City fans group protested after 650 CSKA Moscow supporters gained access to their stadium for their Champions League game, despite the Russian club being ordered to play it behind closed doors for racism offences.