Trailer: Rheinland
From the website:

„During the first World War the French government forced African men – many coming from Senegal or Cameroon – from their colonies to fight for the French army in the Rheinland. ​In 1919, there were between 25,000 and 40,000 African soldiers from the colonies based in Rheinland. After Germany’s defeat, some of the soldiers stayed and founded families.

Their lives, which were already scarred by discrimination and racism were threatened existentially when Hitler and the Nazi-Party seized power.“

They have a crowdfunding campaign but as it’s so often the case there doesn’t seem to be an option to get the film (drm-free &) digital. Not even a DVD if I’m not mistaken (not that I’d be interested in DVDs anymore). So sad.