Spanish Prisoners

i am just guessing but the actor who played the teacher in the 80s hit movie "Stand and Deliver" was in this film...and this film says it is fact based.

Yes, there were Spanish prisoners in the camps: Spanish Republicans and other refugees in exile from the Spanish civil war, they were rounded up - for instance by the French authorities - as illegal aliens, and when France was invaded, they were deported to Nazi concentration camps.

They wore a blue triangle (Jewish inmates had to wear a yellow star, political inmates a red triangle, gay inmates pink triangles etc etc).

Just from France alone, 12 000 Spanish Republicans were deported, mostly to Mauthausen, and Ravensbruck (for the Women).

Spaniards also found refuge in other countries before WW2 broke out: some in Western Europe, some in the Soviet Union, others managed to reach south America.
Quite a few who were still in Europe when WW2 started joined the army of the country they were living in (to fight against the Nazis). Those who were made prisoners weren't considered as POWs (contrary to most westren European soldiers), so instead of being sent to a stalag and protected by the Geneva convention, they were also sent to extermination camps.