Conversation overheard on the Metro, French man talking to an English-speaking couple:

French man: Oh, are you British?
The Couple: No, we're Australian
French man: Not American?
The Couple: No.
French man: Oh, you're very, very welcome in Paris then.

And then he kept talking about how Canadians are welcome and all these other people, but not Americans. Although I have met many French people who are happy to welcome Americans to France, as you can see it's definitely not always the case.