Huh, where? I think there was some retarded law like this passed in Hungary or something recently.
In most countries you can take photos of pretty much anything in the public. The only limitations are usually for commercial use of a photo of a person.
And for that celebrities and politicians have both more and less protections, since they tend to be fair game for quite invasive "press" photos but any attempt to use their image to promote products and services will result in much bigger damages than for Joe Random person.
As for prior consent. Go out to a street in your city, now ask everyone you see for consent to take your typical tourist photo. See the problem? It is unworkable.