Charles de Gontaut, duc de Biron (1562 – 31 July 1602) was a French soldier.
He was the son of Armand de Gontaut, baron de Biron, under whose command he fought for the royal party against the Catholic League in the later stages of the Wars of Religion in France. His efforts won him the name “Thunderbolt of France” (Latin: Fulmen Galliae). Henry IV made him admiral of France in 1592, and marshal in 1594. As governor of Burgundy in 1595, he took the towns of Beaune, Autun, Auxonne and Dijon, and distinguished himself at the battle of Fontaine-Française. In 1596 he was sent to fight the Spaniards in Flanders, Picardy and Artois.
After the peace of Vervins, he discharged a mission at Brussels in 1598. From that time, he was engaged in intrigues with Spain and Savoy aiming at the overthrow of the Bourbon dynasty, the dismemberment of the kingdom of France into provincial states, and his own elevation as sovereign of Burgundy. Notwithstanding these intrigues, he directed the expedition sent against the duke of Savoy (1599–1600). He fulfilled diplomatic missions for Henry in Switzerland (1600) and England (1601), the latter mission being to announce the marriage of Henry to Maria de' Medici. About this same time, he was accused and convicted of high treason by the French parliament. He was induced to come to Paris, where he was apprehended and then beheaded in the Bastille on 31 July 1602.
The tragic fate of Biron was staged by George Chapman (1559?-1634) in The Conspiracy and Tragedy of Charles, Duke of Byron (1608, republished in 1625 and 1653).
He was the inspiration behind the character Berowne in William Shakespeare's Love's Labour's Lost.