Things like whether you have dogs, kids, are a smoker.
Or other things that you're not supposed to discriminate by according to law (looks "foreign", doesn't speak German or with a strong accent).
And then the non-obvious things like your financials (what is the likelihood of paying rent or lack thereof) or connections.
But I think the article doesn't specify actually what they mean by profile.
I had a few follow up questions:
Is this profile usually a verbal communication with you and the landlord then or do they expect to see written proof of those profile details during a viewing appointment?
What would an "reasonable" price be for the mock up listing of the 65 square meter place in Friedrichshain-Kreuzberg be then?
Lastly aside from rent I'm guessing the two biggest overheads are power and internet? What could one expect those to be?
Or have a German ID card (Personalausweiß). Last time I tried to rent there (2017) I had a hard time finding a place as most landlords insisted that I'd be showing them my ID card (mine expired while living abroad). I think without it, it'll be additional hassle with the Einwohnermeldeamt for you and the landlord (not sure about that, but some landlords wont be either).