The franc is any of various units of currency. One franc is typically divided into 100 centimes. The name is said to derive from the Latin inscription francorum rex used on early French coins and until the 18th century, or from the French franc, meaning "frank".
100 Saar francs reverse and obverse
The first franc ever minted, the franc à cheval, was minted upon Jean le Bon's return from captivity from 5 December 1360, and featured combative imagery. Gold, 24 karats, 3.73 g. It conveniently coincided with the account value of one livre tournois.