My boyfriend was running the Frankfurt marathon and the day before he was loading on carbs (but good carbs), and so wanted to go to a Thai restaurant to get some rice. Our hotel in Frankfurt recommended Rama V and said that for many years this place has been voted the best Thai restaurant in Frankfurt. The restaurant is named after King Rama V.
Rama V is located 5-10min away from the main shopping street of Frankfurt and does not look of much from the outside, but the inside of the restaurant is nicely decorated with Thai elements and a large golden Buda. When we arrived at 12.30 we were the only people there, but the restaurant got more busy and by the time we left half the restaurant was full, which just means Germans have their Saturday lunch later than English.