I’m filling in a renting application for a flat. There is one question:
«Wurden Sie schon betrieben?» — Ja/Nein
I can’t figure out what it means in this case. Perhaps it is Switzerland-specific, and I believe it is asking if I was ever in debt?
This is Swiss German. If you owe money to someone (let's say to a bank), and you failed to pay, then the creditor (here: the bank) can call a lawyer to recover the money.
In all regions you can say:
Die Bank treibt Geld von Herrn Huber ein.
The bank recovers money from Mr. Huber.
In Swiss German you also can say:
Herr Huber wird von der Bank betrieben.