Mainly because the French were a bunch of small Kingdoms, Fiefdoms, Baronies, and other minor aristocratic houses that had been handed down to one another for Centuries, and they arrogantly and collectively thought they were too good to be defeated by any mere English peasant “long bowman”.
Napoleon Bonaparte was able to conquer most of France because he united all of those petty principalities into one nation. Until then, nobody with any guts was left of those different Houses because so many of them were slaughtered at Crecy, Poitiers, and Agincourt. The French Revolution finished off what the English long bowmen started...
France had been united for almost 300 years before Napoleon had any power. Maybe you are thinking of Germany.