Marguerite de France (1277/83 - 14 Feb 1318 Marlborough Castle, Wiltshire), was the second wife of Edward I of England. They had three children before he died. Widowed at 26, she never remarried ... and died about ten years later.
I've not seen any source that states that she was married, or even betrothed, to John II (Reginar) of Brabant, either before marrying Edward I or after. I think that somewhere in all the changes she has been confused with her step daughter, also called Margaret, who did marry John II of Brabant.