After World War I, some territories were removed from Germany, most of them had either a majority or a significant minority of non-german-speaking populations.
The exception that comes to mind to me is Saarland, to my knowledge, I do not think there was any significant minority or any population other than Germans in this region. Yet, France decided to create a small independent country that would be under France's influence there, before they would choose whether they would remain independent or rejoin Germany. France tried to influence the country as much as they could but they failed. A referendum to rejoin Germany was extremely successful by gaining 90% of the votes (where the nazis were already in power, making this event their 1st annexation).
After the Second World War, another independent Saarland country was created (I think it had the same territory as the first, but I might be wrong), and, once again, it had eventually joined Western Germany after yet another successful referendum. (This is surprisingly similar to what already happened, but without the nazi thing, fortunately.)
As far I know, both short-lived Saarland independent countries had French as an official language, and they tried (but failed) to create a French influence on the country as much as possible. The French Franc currency was used for money.
My question is: Where does the idea of an independent country there comes from? Was there any French-speaking population there in the first place? If the French would just want to exploit the coal mines, why not just occupy the area but leave it politically to Germany?