Question:
Can someone tell me please why the English were so accomplished with the
long bow and the French didn't use it.
Answer:
England had a Saxon tradition of a universally armed population. I
honestly don't know if this was ever true in France, but if it was
it had declined.
France was generally not an especially united country, particularly
when large parts were occupied by England, others split off under
temerous dukes who like to be considered independent etc. The laws
that required young boys to be taught archery in England were
unlikely to take off in France. Urban populations were generally
well-armed all over Europe, with the crossbow as the weapon of
choice to defend the town's walls.
The Hundred Years War was held in France, a place where French
knights were readily available. Army size is restricted by practical
constraints (like how to feed it). Why have archers when you can
have knights? I believe that an offer of a large force of crossbow-
armed Parisians was declined before Agincourt.