Excerpt from Wikipedia:
She was allegedly cauaght in adultery, and imprisoned for the rest of her life. She was allegedly strangled in 1315, after 2 years of imprisonment, in order to allow her husband to remarry.
She gave birth to one daughter, Jeanne, who later became Queen regnant Joan II of Navarre. Her paternity was under doubts of bastardy. However Joan was an undoubted scion of Margaret and thus a full potential heir to Burgundy. She was also a carrier of Louis IX the Saint.