After the death of her spouse in March 1472, she became regent for her son Philibert until her own death. Like her brother Charles, she was an ally to Charles, Duke of Burgundy, against her own brother Louis XI of France. After the humiliation of Burgundy at the Battle of Grandson in 1476, the duke accused her of being in league with Louis and imprisoned her. After her release, she made peace with her brother and remained on good terms with him until her death. She is said to have been one of the very few women whose intelligence he respected.