UEFA has opened disciplinary proceedings against Manchester City after fireworks were set off during their Champions League quarter-final victory over Paris Saint-Germain.
The charge against City, following the 1-0 win at the Etihad on Tuesday evening which secured a 3-2 aggregate win, relates to Article 16 (2) of the UEFA disciplinary regulations.
The 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.