Fiorentina demanded government intervention after Calabrian-born American owner Rocco Commisso was targeted with chants they branded "racist" before Sunday's 1-0 defeat at Atalanta.
In a statement, Fiorentina's general manager Joe Barone said that Atalanta fans racially abused Commisso, with Italian media reporting chants mocking his southern Italian origins.
Commisso was born in Calabria on Italy's toe but while still a child moved to New York City, where he eventually became an American citizen and a wealthy media magnate, the owner of cable giant Mediacom.
"Today we were witness to a shameful episode, not from an individual but from an entire stand," said Barone, also an Italian-American. "We fought racism in America and today in Italy we have an unacceptable situation. Not only does the league have to intervene but also CONI (Italy's Olympic committee) and the government. We're disgusted and we expect severe punishment."
The 72-year-old Commisso owned the New York Cosmos, who played in the NASL. Its re-classification by U.S. Soccer as a Division 3 league after the 2017 season led Comisso to spearhead a federal lawsuit against the federation that is still pending. Barone is the former NPSL chairman.
In Italy, chants against southerners -- known as "territorial discrimination" -- are taken as seriously as racial abuse of black people due to the history of discrimination against them in the country's wealthier northern area such as Bergamo, where Atalanta is based.
The most common target for these chants is Napoli, southern Italy's biggest and most recognizable club.
In August, Fiorentina was fined 15,000 euros for chants asking for Mount Vesuvius to explode, a chant so popular among soccer fans it even ended up on music streaming service Spotify.
© Agence France-Presse