potato salad

The usual US version of German potato salad is (I think) a Bavarian varient with vinegar and bacon. I've known for as long as I can remember that that was not the only form of potato salad in Deutschland. My American grandmother, whose cooking tended to follow the Germanic traditions of her own mother, made potato salad with mayonaise, as is often common in the US.

Today I bought pre-made potato salad in the market and discovered that the key dressing was neither vinegar nor mayonaise but creme fraîche, which is certainly delightful, though potentially hard on the arteries. I wonder whether this is a Berlin specialty, or north German, or possibly something imported from elsewhere (France? Denmark?) that has become as German as Turkish "Döner Kebab".