The franc (sign: ₣, commonly also FF or F) was a currency of France. Along with the Spanish peseta, it was also a de facto currency used in Andorra (which had no national currency with legal tender). It circulated alongside the Monegasque franc, with which it had equal value. Between 1360 and 1641, it was the name of coins worth 1 livre tournois and it remained in common parlance as a term for this amount of money. It was re-introduced (in decimal form) in 1795 and remained the national currency until the introduction of the euro in 1999 (for accounting purposes) and 2002 (coins and banknotes). It was a commonly held international reserve currency in the 19th and 20th centuries.
The first franc was a gold coin introduced in 1360 to pay the Ransom of King John II of France. This coin secured the king's freedom and showed him on a richly decorated horse earning it the name franc à cheval (meaning "free on horse" in French). The obverse legend, like other French coins, gives the king’s title as Francorum Rex ("King of the Franks" in Latin) and provides another reason to call the coin a franc. Its value was set as one livre tournois (a money of account). John’s son, Charles V, continued this type. It was copied exactly at Brabant and Cambrai and, with the arms on the horse cloth changed, at Flanders. Conquests led by Joan of Arc allowed Charles VII to return to sound coinage and he revived the franc à cheval. John II, however, was not able to strike enough francs to pay his ransom and he voluntarily returned to English captivity.
John II died as a prisoner in England and his son, Charles V was left to pick up the pieces. And so he did. Charles V pursued a policy of reform, including stable coinage. An edict dated 20 April 1365 established the centerpiece of this policy, a gold coin officially called the denier d’or aux fleurs de lis which had a standing figure of the king on its obverse. Its value in money of account was one livre tournois, just like the franc à cheval, and this coin is universally known as a franc à pied. In accordance with the theories of the mathematician, economist and royal advisor Nicolas Oresme, Charles struck fewer coins of better gold than his predecessors. In the accompanying deflation both prices and wages fell, but wages fell faster and debtors had to settle up in better money than they had borrowed. The Mayor of Paris, Etienne Marcel, exploited their discontent to lead a revolt which forced Charles V out of the city. The franc fared better. It became associated with money stable at one livre tournois
Henry III exploited the association of the franc as sound money worth one livre tournois when he sought to stabilize French currency in 1577. By this time, inflows of gold and silver from Spanish America had caused inflation throughout the world economy and the kings of France, who weren’t getting much of this wealth, only made things worse by manipulating the values assigned to their coins. The States General which met at Blois in 1577 added to the public pressure to stop currency manipulation. Henry III agreed to do this and he revived the franc, now as a silver coin valued at one livre tournois. This coin and its fractions circulated until 1641 when Louis XIII of France replaced it with the silver Écu. Nevertheless, the name "franc" continued in accounting as a synonym for the livre tournois.