Where and by whom might french royal power be challenged after 1328?

The French royal power could be questioned because: after the death of Charles IV of France in 1328 there was no male heirs and that ended the main Capetian line. Under Salic law the crown could not pass through a woman (Philip IV's daughter was Isabella, whose son was Edward III of England), so the throne passed to Philip VI, son of Charles of Valois. This, in addition to a long-standing dispute over the rights to Gascony in the south of France, and the relationship between England and the Flemish cloth towns, led to the Hundred Years' War of 1337–1453. The following century was to see devastating warfare, peasant revolts (the English peasants' revolt of 1381 and the Jacquerie of 1358 in France) and the growth of nationalism in both countries.

i really do want to but i just don't know it i'm so sorry : (