With all due respect (I've seen that before somewhere), if I were a resident of Germany and received an email from a powerful German government agency with a strict non-disclosure clause then I probably wouldn't choose Wikipedia as my authoritive source upon which to interpret my rights or liabilities!
That said, I doubt that the Case Number is nearly as high a concern to BaFin as the (now) "published" implication of a "survey" regarding possible PTSC shenanigans.