Standesämtchen is a place I would actually take my parents to if they were in town for a visit. It's not touristy enough, so you can still call it German, but it's frequented by tourists enough that you don't have to be embarrassed to order ketchup or mayonnaise. They serve some of the country's best dishes, and the price ranges from 7-15 euros. You can enjoy the beer garden and the view from ON the Römerberg when the weather is nicer and warmer. It's actually one of the few nice views left of the city of Frankfurt.

Directions:
Directly in Römerberg, overlooking the fountain from its raised platform just near the Pauls Kirche.

Nearest S-Bahn(S):

Nearest U-Bahn(S):
Römer/Paulskirche (U4, U5)

Nearby Attractions:
Römerberg
The Schirn
The Dom