There is no such thing. I mean it will obviously be on his record, but there is no public registry that everybody could look at with consequences for offenders' afterlives. Tbh I find the registry approach, which is a secondary punishment, highly questionable.
The court did the right thing and yet it fucked up. Based on a purely individual guilt approach, what he did probably did not warrant a higher sentence. At the same time, Cologne is a landmark case and people watch closely. There need to be examples made within the possibilities of the law. I am not a lawyer, but I would assume that there would have been opportunities for harsher sentences. Even though probably not in the range that makes things interesting.