Must have walked past it a few times. Came back from a fortnight's break just over a week ago. Just googled it and it looks like it was near Stern Brau where my son had an unfortunate incident with two veal sausages (cue wurst sausage jokes!)
Stayed there for a week in Easter, we got blessed with the weather and were there when Lazio were in town. Austrian food was great but we couldn't stay away from a better and more reasonably priced version of Five Guys...