Hooded youths attacked lines of cops protecting embattled prime minister Matteo Renzi, who was in the city for crunch political talks about the country’s upcoming referendum.
Rioters ripped up cobblestones from the city’s historic streets and hurled them at lines of armour-clad officers, who responded with baton charges and tear gas.
The protesters had massed to express opposition to Mr Renzi’s proposed constitutional changes, which will be voted on in a crunch referendum next month.
Observers in Brussels watching for the result of the vote will have been alarmed by today’s widespread opposition to the plans, which could signal that the government in Rome is facing defeat.
Mr Renzi has vowed to resign if he loses the vote, sparking a general election which would pave the way for the populist Five Star Movement – which wants to ditch the euro – to make huge gains.
The Italian PM has adopted an increasingly anti-Brussels tone to his speeches in recent months as he attempts to battle off the growing eurosceptic movement in his own backyard.
But today anger over his reform plans, which critics say will lead to an excessive centralisation of power in Italy, boiled over onto the streets of Florence.
A crowd of young male protesters broke off from the largely peaceful demonstration and charged police lines in an attempt to reach a building where Mr Renzi was holding political talks.
Florence Mayor Dario Nardella said several police were injured in the clashes but did not give a specific number.
He said: “Hooded people who use violence against the city are deplorable. Saying no is legitimate, destroying Florence is unacceptable.”
However, Italian media reported that one officer was injured on the leg, apparently from a firecracker which was hurled at police lines.
The demonstration was held under the slogan “No to Renzi! No to the referendum!” in protest at the vote, which will take place on December 4.
Polls show that support for the government position has collapsed over the past week weeks, with voters expected to use the referendum as an opportunity to give Brussels a kicking over its imposition of austerity.
The no camp is currently on course to win the vote by a tiny margin, although a large number of voters are still undecided.