The Fifty Francs coin is a denomination of the Swiss Franc. Given that Switzerland has four official languages, the Franc has three different names: Franken in German, franc in French and Romansh, and franco in Italian.
In regular circulation, the denomination is served by a banknote. These gold coins are non-circulating legal tender made for collectors and struck in proof grade only. They are issued in topical series, celebrating various aspects of Swiss heritage or nature. Swissmint has issued at least one every year since 2001. Initially, both sides of the coin carried a commemorative design; starting from 2004, the obverse is the same and only the reverse changes. (It is worth mentioning that some sources consider it the other way round, and call the commemorative part the obverse; however, we are going with the standard definition, which is that "obverse" is the side which specifies the issuing authority).
The edge is inscribed with the motto DOMINUS PROVIDEBIT (The Lord will provide - a quote from the Bible, Genesis 22, 8), and thirteen stars representing the original thirteen cantons of the Swiss Federation.
Note that there was an unrelated earlier gold 50 Francs coinproposed and minted but never released into circulation.