Simone Venturini, the city's former tourism councillor, took the top job last month and has insisted the fee serves as an important deterrent.
He told The Times that while he didn't want to put a maximum limit on visitors, it was important to spread out visitation – especially at peak times.
Venturini said during his campaign the city could seek permission from the Italian government for higher fees of "€30 to €50".
He has, though, suggested ticket-holders could get discounts for attractions like museums.
