[x]

In the teens and 20s there were “Jews Forbidden” signs all over Germany and many other countries.

In the 30s and 40s certainly, but I don't know about before that. People could be anti-Semitic without putting up a lot of signs. Recall that the Nazis temporarily took down those signs during the Berlin Olympics. If they'd been common in Europe, they wouldn't have felt the need.

[golux]

I’m no Wikipedia fan but here’s a link:

https://en.wikipedia.org/wiki/History_of_antisemitism