The laws are different in each country. You’re going to have to trawl through their documentation, I’m afraid. It can be incredibly frustrating. I have a Turkish friend who is a qualified doctor who, despite having the right papers, is still waiting for permission to practice after 18 months here, even though the country is desperate for doctors.
Not a country but a city: Berliners are notorious for being unfriendly but I’ve yet to meet one I didn’t get along with.