The only products labelled "sour cream" on the supermarket shelves here in Germany have herbs in them, meant to be paired with baked potatoes or eaten as a dip with chips. But no worries, fellow bakesters and bakestresses! One can choose from many different dairy products that can work as substitutes for the North American version of sour cream. In the baking world, saure Sahne, Schmand, Crème Fraîche or Sauerrahm could all be substituted for sour cream (but be aware that the outcome of your baked good will vary, depending on the product you choose to use).
I used Schmand to replace sour cream in my coffee cake pictured here, and it turned out marvellously! Schmand is verrrrry thick though, thicker than sour cream. The next time I bake this classic recipe, just to experiment and see how the cake turns out, I'll use Sauerrahm instead (Sauerrahm is not as thick as Schmand; it is closer in consistency to sour cream). Saure Sahne, on the other hand, is more similar in consistency to plain yogurt. I suggest substituting sour cream with any of the above dairy products mentioned at a ratio of 1 : 1 (e.g. 1 cup sour cream = 1 cup Schmand).