France
Rebellions
The worst aspect of Jean's reign was the further deterioration of royal authority. Having the king lose a major battle and be taken away into captivity was bad enough, but in the wake of Poitiers came a widespread rebellion that nearly broke the kingdom asunder.
Everything came crashing down together. In the wake of the defeat, the 
Dauphin, hardly more than a child, had to meet
with the Estates General in Paris and plead for more money to defend the kingdom. As often happened when a meeting of the estates looked to be long and complex, the full body voted a standing committee (of eighty this time, but the numbers varied) to act on behalf of the whole. The leader of these eighty was Etienne Marcel, a wealthy draper and the Provost of Merchants in Paris. The merchants of France had been critical of the government for some time, especially of the financial burden, claiming that much of the wealth of the kingdom was being stolen or mismanaged by corrupt and incompetent ministers. The spectacular loss at Poitiers further discredited the nobility, giving Marcel and the merchants unprecedented influence.
The standing committee's demands were fairly typical: they wanted certain officials dismissed and a new Council appointed to advise the king to be composed of twelve nobles, twelve bourgeois, and four clerics. Essentially, they were replacing the existing royal councillors with their own.
The young Charles refused to accept these demands, which amounted to letting the Estates General dictate his government to him. He dismissed the Estates and left Paris. But the members re-assembled the day after he left and soon Marcel was ordering the people of Paris to arm themselves. The Dauphin was broke and had no choice but to call the Estates General back, to plead again for subsidies. He tried to resist, but the mob repeatedly threatened riot and eventually he signed a document that recognized a Council of Thirty-Six. When King Jean learned of the agreement, he immediately rejected it completely. But Marcel ruled Paris, the King was a captive, and the Dauphin had no money and no army.
This lasted into the summer of 1357, when revolts and riots across France made the situation even more serious.