The woman, in her early 20s, faces charges of public obscenity for skinny-dipping in the modern fountain above the Apple store in Milan's Piazza Liberty.
Alarmed onlookers told police they'd seen a naked person under the water at around 10pm on Wednesday night, though by the time officers arrived the woman had reportedly put on some clothes offered her by passersby and was heading away from the scene.
"I didn't think it was forbidden in Italy," she told police, according to Ansa. "I didn't think I'd done anything wrong."
The woman was not under the influence of drugs or alcohol, police sources told the news agency. The weather on the evening in question, according to one local paper, was "rather fresh".
Photo: Piero Cruciatti/AFP
The Piazza Liberty fountain, which debuted last summer, isn't a historic landmark, but Italy has strict rules banning disruptive behaviour in its tourist hotspots.
Bathing in historic fountains is strictly forbidden and can carry fines of several hundred euros – not that the risk puts certain visitors off attempting their own 'Dolce Vita' dip.
Several cities including Rome and Florence have restrictions on where people are allowed to eat, drink alcohol or even sit around their landmarks, while Venice has had to ban bathing suits and bare chests from its city centre.
READ ALSO: Venice to kick out visitors caught behaving badly