What advantages did the king of France have in the fight against major feudal lords?

In the period of the mature Middle Ages in France, the need for a strong centralized government was increasingly felt. Powerful feudal lords, who owned huge duchies and counties, formally obeyed the king, but in fact they often ignored his orders, based on their personal benefits and ambitions. This hindered the development of the country’s economy and defense capability. In the fight against influential feudal lords, the king’s side was primarily artisans and merchants, who benefitted from centralized government with a unified system of taxes, trade rules and a unified monetary system. The king was also supported by the petty nobility, hoping to receive significant preferences from him for this.