DrYidd, the Lubavicher Rebbe was an enrolled full-time student at the Sorbonne, after graduating from ESTP, which is one of the most prestigious civil engineering schools in France. Since you’re so wrong about that, you’re not reliable about Berlin either.
What records do you think should exist for Hildesheimer students who took classes at the University? Do such records exist for the dozens or hundreds of other students who did this? And how do you know?