Your Line of Business?
You want to ask someone, “In welche Branche arbeiten Sie?”
What do you say in English?
You need to be careful here, because you can’t use the English word ‘branch’. A ‘branch’ translates as ‘Zweigstelle’, ‘Filiale’ or even ‘Ast’ in German!
What you can ask is, “What industry/field/sector/line of business do you work in?”.
And your conversation partner might answer, “I work in the consulting industry. My company has branches in several countries. I work in the branch in Germany”.
So what line of business do you work in?