This is an interesting piece - thanks for sharing. The black band/red piping is artillery, pioneer, or technical troops. If it looks blue in person, that would likely be from either sun or chemical fading (a legit blue band with red piping would be an army surgeon, which this is probably not).
Another possibility might be prisoner of war. A lot of wartime photos of German POWs show the cockades missing (removed for Entente souvenirs maybe?) And it certainly looks like a homemade sun shield complete with ventilation holes. Maybe a crafty POW interned in a open, sunny camp? Just my $0.02!
~Jeff