Actually, it's mostly influenced by Italy aside from accents. Rivain is mostly influenced by Spain aside the accents.
It's more 'inspired by'. Basically Antiva city itself is inspired by Venice, but this inspiration did not go any further than a 'commercial maritime city dominated by wealthy businessmen' and the use of the names of Rialto (a neighbourhood in Venice) and Treviso (a city in the old Venetian Domini di Terraferma, i.e. Venice's mainland holdings). Since commercial maritime cities ruled by big businessmen are pretty common in ancient and medieval western Eurasian history, the only distinctively 'Italian' things about Antiva are the names of Rialto and Treviso. Change those names and there isn't anything left.
One might argue that the Crows, a feared and powerful criminal organisation, are based on the Italian mafia, but to be honest they seem to be far more similar to the assassin's guilds and other criminal groups that are common to mainstream generic fantasy settings from Toril to Thedas.

In fantasy, you can't have a major commercial city without a powerful criminal organisation, it seems... 
Little known fact: Antiva, which replaced Calabria, is the name of a brand of office equipment, as well as that of a type of medication used for treatment of Hepatitis B.
Antivans...they shred you or they poison you...

