[Minato Ku]

Centro direzionale di Napoli hosts at most 1 million m² of office space.
It is not a lot, It is not even sure that this is the main business core of Naples.

I would be quite cautious about the so called visible business cluster, it is not necessarily representative of the economic power of the city.
In many European cities, business cores with many office buildings are usually less visible than in the American or Asian cities because they are not much architecturally different that a dense residential district.

By example there are more office space in Rome than in Hong Kong. I think that this fact would suprise almost everyone.
Don't be fooled by the visibility, often the reality is not what it seems.