Open borders with the rest of the EU is...Spain, Germany, Switzerland, Belgium. ...

Symbiote · on Sept 17, 2021

There are usually no border controls from France as far as the EU borders with Russia, Belarus, Ukraine, Serbia and Andorra.

Romania and Bulgaria's borders seem fairly porous, and Bulgaria borders Turkey.

There is a marine border with North Africa, which is probably the closest equivalent to the US/Mexico border.

philwelch · on Sept 17, 2021

There's also Hungary, Poland, Romania....