Roma were ordered to close both the Curva Sud and Curva Nord sections behind the goals for two home games because of anti-Naples chanting in a cup match against Napoli, a sanction which began at home to Sampdoria last Sunday.
However, Italy's sporting tribunal said that fans in the so-called "Distinti Sud", a more expensive section of seating adjacent to the Curva Sud, themselves took part in anti-Naples chanting during Sunday's game.
"This conduct involved around 90 percent of the roughly 6,000 spectators occupying that section," said the tribunal in its decision on Tuesday.
The Italian federation announced automatic stadium closures for discrimination by fans at the start of the season, a measure originally seen as intended to target racial discrimination.
However, it has also been used to combat so-called territorial discrimination, a move which has been fiercely opposed by hardcore fans.
Napoli fans themselves unfurled a banner at one game which read: "Naples cholera-sufferers. Now close our curva!")