― My blog reader asked me, what is RF on euro coin? He found out that some of his euro coin has a RF letters on them but most of it don't have that letters. He thought that coin maybe rare or the letters are some kind of watermark or something. Exactly, RF initial stand for République Française (French Republic). The coins that he is talking about are French Euro coins. All French Euro coins has that initial on them. There is nothing special about that coins. The letters RF has also been used [...].