Paola, a local shopkeeper, said: "I'm ashamed, you understand. Planting a plastic urinal like that beneath the windows of the Lauzun mansion, one of the most beautiful on the island, where [the poet] Baudelaire lived, it's such bad taste. Paris is making itself ridiculous."
Paola acknowledged that residents had long been urging the authorities to install urinals because young people who spend the long summer evenings on the banks of the Seine had taken to urinating in the streets.
"But this model, 20m from a primary school, is not suitable at all."
Wouter, 43, a visitor from Amsterdam, said he had used the facility, but felt uncomfortable. "Public toilets are usually more hidden. At first I thought it was a modern art installation because of the flower box on top."
The urinal is "environmentally friendly", according to its manufacturer, the Faltazi design agency, because it "stores urine in a bed of dry material, straw, which is then used as compost for the flowers".
The straw reduces odour and eliminates the need for the urinal to be connected to the sewer. Four minimalist urinals installed in Paris in the past six months have drawn similar reactions from the public. A fifth is planned next week.
The mayor's office said they are "a response to the needs of shopkeepers and residents".
Victor Massip, the inventor of the model installed on the Île Saint-Louis, said: "People urinating on the streets of France is a serious problem and we knew there was a demand for a solution, so we've come up with one."
He has named it the "uritrottoir", combining the French words for "urinate" and "pavement".
Bill Wilson, 50, a visitor from Leicester, said: "I think this wouldn't be allowed in the UK. Only in France!"