.at

A .at belongs to organisations whose market is Austria: a hotel in Tyrol, a fitting company in Graz, a shop that only delivers within the country. German and Swiss firms with Austrian customers use it as well, because a .de raises the question of who actually handles the customer.

There are no registration conditions, so no local establishment is needed. That makes it usable from abroad: the address says something about who you are serving, not about where your office happens to be.