your countrymen who were fighting for the freedom of other people

I am somewhat sceptical towards the NKFD.  i think it was less a means to fight Hitler, than a preparation for the communist governement in whatever parts of Germany the soviet union would control.

I think there were quite a lot of german communists in the international brigades during the spanish civil war. lots of italians as well, and both germans and italians on the side of franco.

another prominent german communist in foreign service at that time was Otto Braun (not the prussian premier), who served as comintern counselor to mao zedong. mao didn't like the comintern, and complained to braun that chiang kaishek's germans (von seeckt and von falkenhausen) apparently were better than those of the comintern. nevertheless, Braun took part in the long march, and he later published a book on his experiences.

after the war, many germans fought in the french foreign legion (e.g. in algreia, or dien bien phu), but obviously not for the freedom of other peoples. some of them changed sides, though.

edit: falkenhayn->falkenhausen (falkenhayn was a general during WWI)