[chopin]

Which ones? I never came across any. They may require a "Personalausweis" (like banks) but not a passport (which is a different thing). An EU citizen can come well by without ever needing one, as he can travel the EU by personal id alone. I only need a passport for international travel.

And that makes sense. You can be denied a passport, but not a personal id.

[socksy]

I have definitely experienced the case multiple times online where I have been denied something without a German Personalausweis or a passport. In my case, as a UK citizen I don't have a national ID card, so Passport must do, but the option is never "generic ID card" vs passport, but instead the German Personalausweis. Schufa is guilty of this, and iirc so is ImmoScout.