The ferry port in Messina, Sicily. File photo: AFP
The six-month penalty was applied to the 'Caronte & Tourist' ferry company for favouring the interests of the 'Ndrangheta, the notorious mob from the southern Calabria region.
Caronte & Tourist is a well-known operator in Italy, which holds a de-facto monopoly on ferry connections over the Strait of Messina, which separate Sicily and Calabria.
According to Italy's anti-mafia police, the company farmed out lucrative catering, cleaning, and ticket booking services to 'Ndrangheta-controlled companies.
It was said to have hired a couple of 'Ndrangheta mobsters who used their position as insiders to steer business towards their criminal associates.
Authorities seized assets worth 800,000 euros (962,000 dollars) from one of them, Massimo Buda. He was described as the son of a jailed Ndrangheta clan leader.
The 'Ndrangheta – considered Italy's richest and most powerful crime syndicate due to their control of most of the cocaine entering Europe – is currently the target of a massive trial in Calabria involving over 300 defendants.