If I was hiring, I would hire homosexual Martian Nazis if they made good employees. The few African colleagues I have had were skilled and pleasant. The trouble is that, at least in the U.S., that they are very rare.

I suspect that a lot of what you were seeing in France was selection bias. The most talented third-worlders immigrate at a very high rate to the former imperial states. France gets the Africans because they colonized Africa extensively and were not especially vicious. If you moved your company to Rwanda, you would find that very very few locals would be trainable for engineering work.