And Nazis and Communists got along real peachy from August 1939, to June 1941.
According to Erik von Kuehnelt-Leddihn's book "Leftism Revisted", the Nazis and the German Communists originated from the same splinter groups of German Socialists.
He asserts in his book that the Nazi Flag, (Red Background/White Center with a Swastika) Were originally made from Communist "Hammer and Sickle" flags over which a Swastika was placed to cover up the Hammer and Sickle. That is why the Nazi flags were Red. The original Communist flags from which they were made were Red.