An Italian football appeals court made the decision on Wednesday.
The abuse occurred during a 3-2 away win for the Rossoneri in Udine
The court of first instance ordered the whole ground closed for one game, a ruling Udinese appealed.
The episode has been condemned by Italian, European and world football bodies.
Udine’s city council earlier this week rejected a leftwing motion to grant Maignan honorary citizenship of the northeastern Italian city.
ANSA