The trial will continue for the next 30 days when the number of visitors to the city is expected to be especially high.
Visitors will have to book tickets online in advance.
Residents, commuters, students, children under 14, people staying in the city overnight and people visiting for sporting events will be exempt from having to buy the ticket.
“We have a duty of preserving these great historic centres of the world,” said Mayor Luigi Brugnaro at a press conference launching the initiative.
He said it did not mean that “the city will be closed” and denied the move was aimed at raising money for the city council.
Brugnaro also said Venice would not cap entries, but only make people pay to see the historic centre.
ANSA