It used to be that you could take photos (without flash) in most of the churches and museums here in Florence- but with the advance of digital cameras (where everyone can get reasonable images even with a $100 camera) many places have outlawed cameras, even without flash.
The theory among us common folk is that the museums and churches closed to photography once they saw their gift shop sales diminishing and realized that tourists wouldn't buy books if they were able to take somewhat reasonable pictures themselves. So, instead of "no flash" symbols there are now "no Camera" symbols.
but sometimes you just can't help but take a risk.........
(Breakin the Law, Breakin the Law!)