In Venice, new rules have been adopted on the size of tour groups and the ban on the use of loudspeakers and megaphones for tour guides. It is one of a series of measures that the city government of Venice has adopted in the past year, with the aim of protecting the city from intensive visits.

Venetians welcomed the decision, which has exemptions for children under two, school groups and educational and professional trips. The rules also apply to the islands of Murano, Burano and Torcello.

The restriction was supposed to take effect in June, but was delayed because many guides had already booked group tours around the city with groups of more than 25 people. Guides who break the rules can face fines from 25 to 500 euros.

The use of megaphones, "which can cause confusion and disturbances", is also prohibited.

The city's security official, Elisabetta Pesce, has stressed over the past year that the policy is aimed at improving the movement of groups through the historic center of Venice, as well as the highly visited islands of Murano, Burano and Torcello.

Venice has become the first city in the world to introduce an entry fee system for tourists, in a bid to ease congestion during the peak tourist season and holidays.

Last year, Venice narrowly avoided being placed on UNESCO's "World Heritage in Danger" list, in part because the UN body recognized the city's efforts to prevent Venice's delicate ecosystem from being overwhelmed by mass tourism.