My grandfather from mothers side, and his brother went looking for work to Belgium in the early 1930s', worked as miners there for some time to eventually end up in French Foreign Legion in mid 30's, they were sent to Algeria and some other colonies too. By the time of WWII their Regiment was stationed in France, but Im not sure what was their combat history. All in all both ended in POW camp until liberated in '44 by Americans. Then my grandfather returned to Poland shortly after the end of the war, his brother on the other hand returned to the Legion, he was a sergant there. Later his unit was sent to Indochina where he died on malaria in 1947, but certain date still remains unverified.
My grandfather from father's side was a Russian, a talented engineer he worked at some military facility during WWII.