In episode 6 of Star Wars Rebels ("Empire Day") I noticed the Imperial Crest being displayed in a black/white/red color scheme in a few scenes of the episode, distinctly resembling the colors of the Nazi flag.
I've seen all of the released movies (including bonus material from the DVDs), watched The Clone Wars TV Series and the film as well as having read related magazines (and played a few games set in this era like Empire at War, Jedi Knight 2 and 3), but I cannot remember the crest being displayed on a particular color background – It's normally black, white, grey or no background.
Is it just me? Have I overlooked something in the media listed above? Has the crest been depicted like this in other media previously?
I'm interested in both in and out-of-universe answers. Does this relate solely to Empire day or have we seen it elsewhere?