France
New King, New Beginning
Jean's younger son Louis was the one who violated the treaty terms. The older son was a much more sensible fellow and it was he who succeeded as Charles V (1364-1380). He had been on the field at Poitiers and found he didn't care for battle. He was instead a capable administrator and a good judge of men. He was able to stem the losses France was suffering and was even able to recover a good bit of ground.
After Jean the Good, Charles earned the sobriquet "the Wise" for he was more intellectual and more methodical than either his father or his grandfather, both of whom were far removed from either of those two characteristics. Charles sponsored 
Nicholas d'Oresme and founded the library at the Louvre. When deciding how he was to be portrayed in some illuminated manuscripts, Charles chose to be shown in academic garb.
But you should not picture the king as some bookish recluse. He began ruling even before he was king, for he was named regent while his father was taken as a captive to London in 1356. The young Charles rode from the terrible loss on the battlefield straight to Paris, where he summoned the estates and had immediately to deal with the simultaneous threats of Charles the Bad of Navarre, the peasant revolt known as the Jacquerie, and the rebellion in Paris itself led by Etienne Marcel. This lasted for two years, and Charles had to participate in the treaty negotiations that freed his father. It took strong leadership simply to hang onto his crown.
Once he was king in his own right, though, Charles enjoyed some victories. The most notable was that of the great general Bertrand du Guesclin over Navarre in May 1364. After that defeat, Charles the Bad was effectively removed from Normandy and restricted to the south of France. In the west, Charles' generals were able to drive the English out of many of the lands they had conquered, forcing the enemy back to Guyenne itself.
Even so, the setbacks were likewise serious. Brittany was lost to John of Montfort, supported by the English. And Burgundy began its rise to power. During Charles V's reign, however, Burgundy was not yet a threat.