Just german things : Einmarsch = Invade

What she said. I guess it is pointing to the entry of a building and the word for that in German is equivalent to invade (or possibly incorrect here). Appears to be the French flag - Germany invade France? Seems like it'd be more of a Poland thing...Idk. Mia, tell me I'm stupid and explain this please. Pretty please. Plz. Pweez. Please!

You're not stupid, you hit the nail on the head :)