I just found a few Information about this. (Also Sparkasse)
"In order to open a bank account, each customer needs
suitable identity and legitimation documents. You need
to show one of the following documents to the consultant
of the Sparkasse:
a passport
an ID-card, issued by a German authority
a passport replacement document, issued by a German
authority
a preliminary residence title for specific purposes,
if this includes personal information and a photo
an exceptional leave to remain, issued by a German
authority, if this includes personal information and a
photo"
you can find more about it here:
https://***.sparkasse.de/geld-leichter-verstehen/s/sparkassen-girokonto-informationen-fuer-fluechtlinge-und-helfer.html