Now I understand this is difficult, perhaps even borderline ASB, but is there any remote chance that an independent Republic of Alsace-Lorraine can be formed and survive both French and German interests in the region and lasts, not necessarily until the present day, but for a significantly longer period than its OTL equivalent.
To make this challenge slightly easier for you, I will give you a free hand in the PoD. So anything after January 1900 is allowed.
What can you think of?