They are not Chinese German, they are the 800 Chinese troops holding out at Shanghai against the Japanese covering the retreat of the Nationalist forces. Is from the movie The 800 I think, they wear German gear since Germany provided them with weapons and gear before WWII broke out in Europe.
China and Germany had quite a good relationship before world war II broke out.Nationlists formed some units equipped with German equippments and also trained by German officers.But due to the fact that China was a backward agricultural country,they can only form very few of these German-like units with a low military
Chinese (German trained unit) hold out at Shanghai would be a better title as that is what this film is based off of. They wear Stahlhelms and use German equipment such as Stielhandgranate’s and Mauser Karabiner 98K’s as Germany supplied them with that equipment prior to the invasion of Poland (September 1939.) also an extra note, the Sino-Japanese theatre of WW2 (and prior to the break out of WW2) was probably one of the bloodiest theatres you could have possibly fought in. Also, the battle of Shanghai is sometimes referred to as “the Chinese version of Stalingrad” as it parallels the Soviet battle for Stalingrad on the eastern front (during the German invasion of the USSR, советский-союз.)
If I'm not mistaken, I read they were a special battalion that was trained by the Wehrmacht. Only they had the gear and clothing that look exactly like pre-WW2 German soldiers. Too bad they don't have anti-tank weapons or heavy machine gun, they have to use themselves as body shield.
Later, the Japanese would hand over various captured goodies from the Chinese to Japan's auxiliary troops. My grandpa serve in Kyōdo Bōei Giyūgun (Indonesian Homeland Defender) and he was issued with stahlhelm and Gewehr88. Cannot really confirm the gewehr since he passed away decades ago and the only photo about him while still in service shows that he actually carried British Sten gun.