Celtic have been fined €10,000 euros (£7,300) following the actions of a section of their supporters in their Europa League tie against Dinamo Zagreb in Croatia.
UEFA held disciplinary hearings against the Scottish champions after flares were set off among visiting fans during their 4-3 group-stage defeat last December.
Celtic had pleaded with their supporters to behave responsibly prior to the game at Stadion Maksimir.
A statement on the club's official website read: "We stress the dangers surrounding fireworks and pyrotechnics which are considered a serious safety issue. The discharge of such items, not only creates a hazard to spectators but will expose Celtic FC to disciplinary action by UEFA."
This is the fifth time that Celtic have been charged by UEFA following fan incidents.