The livre was the currency of France until 1795. It was subdivided into 20 sous (also sols), each of 12 deniers. Several different livres existed, some concurrently. The livre was the name of both units of account and coins. A solidus (the Latin word for solid) was originally a gold coin issued by the Romans. ... Denier can refer to: Denier, linear density of mass in fibres. ...

The livre was established by Charlemagne as a unit of account equal to one pound of silver. Only deniers were initially minted but debasement led to larger denominations being issued. Different mints used different weights for the denier leading to several different values of livre. The two most important of these were the livre parisis and the livre tournois. These were related to one another by 4 livres parisis = 5 livres tournois. Charlemagne (742 or 747 – 28 January 814) (also Charles the Great; from Latin, Carolus Magnus or Karolus Magnus), son of King Pippin the Short and Bertrada of Laon, was the king of the Franks from 768 to 814 and king of the Lombards from 774 to 814. ... The livre tournois (or Tournoise pound) was a currency used in France, named after the town of Tours, in which it was minted. ...

Between 1360 and 1641, coins worth 1 livre tournois were minted known as francs. This name persisted in common parlance for 1 livre tournois but was not used on coins or paper money.

The first french paper money was issued in 1701 and denominated in livres tournois. However, the notes did not hold their value relative to silver due to massive over production. The Banque Royale (the last issuer of these early notes) crashed in 1720, rendering the banknotes worthless.

In 1726, the livre tournois was adopted as the sole standard for the French coinage, although coins worth 1 livre were not issued. Instead, silver coins called écu were issued worth 6 livre, along with ⅛, ¼ and ½ écu denominations (15, 30 and 60 sols). Copper coins of 3 and 6 deniers and 1 and 2 sols were also issued, together with gold Louis d'or, worth 24 livres. The term écu may refer to one of several French coins. ... The Louis is any number of French coins first introduced by Louis XIII in 1640. ...

Paper money was reintroduced by the Caisse d'Escompte in 1776, denominated in livres. These were issued until 1793, alongside assignats from 1789. Assignats were backed (in theory) by government-held land. Like the issues of the Banque Royale, their value plummetted.

The last coins and notes in the livre currency system were issued by the Year II of the Republic (1794). In 1795, the franc was introduced, worth 1 livres 3 deniers.