The footpath collapsed on the Lungarno Torrigiani, a road alongside the Arno River that is not far from the famous Ponte Vecchio, part of the city’s historic centre, a UNESCO World Heritage site.
Dario Nardella, mayor of Florence, wrote on Twitter that no injuries had been reported and that firefighters had been sent to the scene.
According to The Associated Press, Nardella said the sinkhole had been caused by a large gash in the pipe, which is about 60 centimetres in diameter and is one of the main sources of water for the surrounding neighbourhood. There was no leak in the banks of the Arno, the mayor said.
Nardella also urged people with cars parked on or near the Lungarno Torrigiani to remove their vehicles.
There had been concerns that the saturated asphalt would be unable to handle the weight of cranes, but some machinery was seen removing a number of the sunken cars later in the morning.
Two buildings near the hole were evacuated, localauthorities said.
Access to the neighbourhood was restricted, and the water supply was temporarily cut in nearby areas while technicians tried to fix the broken pipe.
Emergency services were expected to take thousands of bottles of water to 18 schools in the city.