Please note that these restaurants are good and chosen from personal experience. But despite my good experiences (and most times regular visits) it is always good to double inform the staff that you are on the diet.
Special warning: no restaurant or food can be 100% guaranteed to be safe despite their best efforts. It is always possible that food gets contaminated with gluten. Author of this guide and website do not take responsibility for your choice and health situation. In case of any doubts you should not use this guide.