How did France, in the early modern period, come to be some much more centralized than the Holy Roman Empire?

My vague understanding, in part from Crusader Kings, was that in High and Late middle ages, both the Kingdom of France and Holy Roman Empire had a weak ruler, where Dukes and Counts had considerable autonomy and the power of the ruler depended in large part upon his personal relations with his powerful subject. How did power structures of the two polities come to diverge?