Mayor says Rome's historic and artistic heritage belongs to everyone.
Rome mayor Virginia Raggi has pledged a zero tolerance approach to "unacceptable behaviour" at the city's historic fountains.
"Our monuments must be respected and Rome's historic fountains are not swimming pools", Raggi wrote on her Facebook page.
The mayor posted a video of a man, dressed as an ancient Roman senator, who had to be escorted out of the Trevi Fountain by police on the evening of 15 July.
The 38-year-old Italian was reportedly protesting in favour of traders in Campania, victims of the Camorra, and demanded to speak to Italy's interior minister and deputy premier Matteo Salvini.
The protestor was handed a €550 fine, as well as a temporary ban or "daspo" from returning to the area, under Rome's new urban police regulations.
Raggi stressed that these measures would apply to "anyone who offends the historical and artistic heritage of the city, which belongs to everyone."
The mayor's intervention comes amid continuing headlines over bad behaviour in the capital's fountains, normally involving foreign tourists - unwittingly or otherwise.
On 13 July the Trevi Fountain was closed to visitors for two hours due to the excessive amount of tourists, who threw their customary coins from street level.
In recent days the British embassy to Italy issued new travel advice, warning UK tourists not to bathe in Rome fountains.