West Ham and Fiorentina have been charged by Uefa in relation to incidents at Wednesday's Europa Conference League final.
Both clubs have been charged with "throwing of objects" while the Hammers have also been punished for "invasion of the field of play".
Fiorentina captain Cristiano Biraghi was struck on the head by something thrown from the West Ham end in the first half of the game in Prague.
The Hammers won the match 2-1.
Fiorentina have also been charged with "lighting of fireworks". Uefa says the matter will be decided in due course.