This is an excellent AND quite affordable restaurant close to the south station (Südbahnhof). They offer potato-based traditional German, international and creative dishes. The few dishes that are not (!) gluten-free are marked on the menu. I have celiac disease and lactose intolerance (+ I’m a vegetarian!). I asked them to make a potato pizza without the sausage and with lactose-free cheese I brought. It was the first really really good meal I’d had for ages, and I’ll definitely go there again!