An agreement signed by the city council last week will force new businesses to sell local, traditional foods chosen from a list of produce drawn up by the region of Tuscany.
The city's historical centre is a Unesco World Heritage site which is visited by millions of tourists each year.
However, the city's Democratic Party mayor Dario Nardiella says the city is losing its character due to the growing number of kebab shops and mini-markets selling low quality foreign products to tourists.
“This measure comes at a difficult time for the city,” Nardiella told La Repubblica.
“Deregulation by previous governments has removed controls on what food products can be sold, which has led to a distortion of the centre's food culture."
Nardella said the huge number of shops and restaurants profiting from the tourist trade could damage the traditional feel of the centre unless regulations were introduced.
“One restaurant opens every week in the historic centre. Mass-produced foods are replacing our traditional trattorias and historic food shops: we have to put an end to it.”
The long list of local produce the council wants shops to sell includes some of the most iconic items in Italian cuisine, such as Chianti wine and pecorino cheeses.
It also includes lesser-known but highly-prized regional varieties like the pearly white Sorana bean or Garfagnana spelt.
“The ruling is retroactive for all shops, but not restaurants, in the historic centre too,” Stefania Crivaro, a spokesperson for the city council, told The Local.
"They now have three years to ensure that 70 percent of their produce is locally sourced."
Crivaro said the decision was not a ruling against ethnic foods and shops would be allowed to sell less than 70 percent local produce in some circumstances.
"A five-man commission working to ensure the city's food culture and feel of the historic centre will grant approval to businesses that don't want to sell local produce on a case-by-case basis."
While the initiative has won praise in some quarters, Oscar Farinetti, founder of global Italian supermarket chain, Eataly, said new rules could prove too restrictive and damage business.
“It's sensible for regions to protect their biodiversity but 70 percent might be a bit too high,” La Repubblica reported him as saying.
But the scheme could be rolled out in other historic cities soon.
“We've been getting lots of calls from councils up and down the country who are curious about the idea and are hoping to introduce something similar to their historic centres," Crivaro added.