Since i am in Florida I was thinking Tampa and Miami. 

Tampa can have Ybor City and Downtown and Westshore.

Miami can have Downtown and Miami Beach and North Beach.

I think this is brought up in a older post but as im from St Paul MN Id like to suggest the twin cities as a potential new city. There was a rich history of gangsters here including caves where bootleggers smuggled hooch and even a speakeasy, https://www.minnpost.com/mnopedia/2015/11/crooks-haven-gangster-era-st-paul/

Also the chief of police in St Paul had a deal, you stop in the police station and report you are there, pay a bribe and promise not to commit high level crimes in St Paul (Minneapolis was ok). Several characters including Dillinger, Capone and Ma Barker and her boys had a 2nd home in St Paul 

There is also a rich history of gangsters in Tampa and Miami