John Theune wrote:

What cities do not allow GA near/over them? I've not heard of any.

Paris for sure is Class A to the ground. Other cities in France have
rules according to their size, which typically make it "de facto"
impossible to fly over them. It is possible to fly over towns and
smaller cities in France.

I'm not sure about London - I go there often enough, and I've never
seen a small plane over the city - so I'm guessing it goes about the
same way there. Again you do see VFR traffic over smaller UK cities.

Switzerland, I believe, is very restrictive as well.

GF