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!"
(Writing by Brian Homewood in Berne; Editing by Rex Gowar)
