The Irish Football Association has been fined 3,000 euros (£2,120) over the firework incident in which a press photographer was injured.
It happened during the Euro 2016 qualifier between Northern Ireland and Romania at Windsor Park on 13 June.
The IFA said it had used video evidence to show the firework had been thrown from the section of the ground where Romanian fans were accommodated.
The Romanian FA is facing a charge over prohibited banners at the match.
Uefa said the decision on that matter would be released by the end of this week.
Officials at the Irish FA had hoped to escape with a warning over the firework incident.
However, they have indicated they will not appeal against the fine as the amount involved was small.
The photographer struck by the missile needed medical treatment for neck and ear injuries.
The incident happened at the railway end of the Belfast ground during the second half of the match which ended in a 0-0 draw.