Fransk greve og ridder. Anførte den anden franske linje under slaget ved Agincourt. Dræbt under slaget. Hans søn blev senere taget til fange af englænderne.
Jean, duc d'Alençon, lost his father at Agincourt in 1415, and as soon as he could do so, at the age of eighteen, he took up a career in arms, seeking to recover the lands held by the enemy. He married, in 1423, Jeanne, daughter of Charles d'Orléans and Isabelle of France. As lieutenant-general of the Dauphin in Normandy, Jean fought in 1424 the unfortunate battle of Verneuil, where so many lords of France and Scotland were lost. He was taken prisoner by the Duke of Bedford, and held for three years at Crotoy until he paid 200,000 saluts d'or for his ransom. He sold all he possessed to the English, and his fief of Fougères to the Duke of Brittany. When he left prison Jean d' Alençon was "the poorest man in France."
Faithful to France, having nothing to lose and everything to gain, the duc d'Alençon took command of a company of men-at-arms. We know how he led in the Maid's enterprises everywhere, and the confident friendship that Jeanne had for her "beau duc." Jean hoped to lead her sometime to conquer his duchy of Alençon in Normandy. About 1440 Jean d'Alençon who had until then the highest renown for prowess and fidelity, changed all at once. He took part in the revolt of the princes, received the Toison d'Or, had himself dismissed from his office as lieutenant-general, and believed that he was persecuted by the Count of Maine, and said that the King mocked him and did not treat him as he deserved. Jean talked indiscreetly, entered into relations with the English, promised them Granville, gave himself up to drinking, women and magic. On May 3, 1456, Jean testified at Paris at the Rehabilitation proceedings, but he was arrested on the thirty-first by Dunois. He was condemned to death by the peers of France in 1458 as guilty of lèse-majesté, but he was pardoned and freed upon the accession of Louis XI to the throne. d'Alençon was again condemned to death at a second trial in 1474, and this time, too, he was set at liberty. He died in 1476.