The Valois dynasty in the long run created more problems for France than it had accomplishments. Their policies of religious intolerance and selling of titles for nobility created enormous difficulties.
France, finding itself surrounded by the Holy Roman Empire on each side, had fought against the Empire in the Hapsburg-Valois War. The war had been expensive, Francis I (who also lavished himself with expensive paintings and other luxuries) sold titles of nobility to raise money. These "nobility of the robe" held positions which soon became hereditary. Since he nobility did not pay taxes, the end result was the reduction of the tax base in France, thus leading to financial difficulties which would ultimately lead to the French Revolution.
The Concordat of Bologna, signed by Francis with the Pope, gave the French crown the right to name French bishops and Abbotts. In exchange, Francis recognized the supremacy of the Pope over church councils. The end result was to make Catholicism the official religion of France. This occurred at a time when many French noblemen were attracted to Calvinism, primarily for political reasons. These so called Huguenots were bitterly persecuted by the Valois monarchs in an attempt to eradicate Calvinism from France. The end result however was to actually encourage the growth of the Huguenots.
On August 24, 1572, St. Bartholomew's day, Charles IX with the encouragement of his mother, Catherine de Medici arranged a meeting with Huguenot leaders to discuss peace. The Huguenots were encouraged to leave their weapons behind as a token of their sincerity. During the night, the Catholic forces fell upon the Huguenots and slaughtered them in the famous St. Bartholomew's day massacre.
The last of the Valois line was Henry III, brother of Charles IX. Henry was openly homosexual and had no heir. The resulting civil war for control of the French throne was known as the War of the Three Henries. It ended when Henry of Navarre converted to Catholicism, reputedly after commenting that "Paris is worth a mass," and was crowned Henry IV.