Ultimately, it would fall on the French Revolution to create a proper sense of the idea of a national identity, the seeds started during the Hundred Years War and the reign of Charles VII.

While I cannot effectively go into great detail with the Hundred Years War, it provided one important part of the creation of the nation of France, a central power. Now the centralization of France comes not from a need to increase national identity or efficiency of political effects but rather to ensure the cohesion of loyalty of the nobility to the King. Many players during the Hundred Years War were nobles that were "French" by culture and language but sided with the English or French depending on their needs. With the crown gaining power and focusing it towards the defeat of the English, it gained a centralizing effect on France that would last for a few decades. However it would eventually fall apart under the rule of Louis XIII and lead to the Fronde, a revolt of nobles against the King of France to establish older "feudal" powers that were essentially taken away from them by the centralization of France.

It would be Cardinal's Richelieu and Marzain that would help shape Early Modern France into that of centralized power. With the ascension of Louis XIV to the throne, the Fronde was coming under control and Louis was under the education of Marzain, learning about the importance of influence and power. When Marzain died, Louis XIV would propel France forward by unifying the nobility geographically by pulling them to Versailles in order to keep an eye on them and play them against each other in order to force obedience and loyalty. Under Louis, France became truly centralized with the nobility becoming either servants of the state or neutered courtiers.

Slowly France will fall not because of her military failures but rather because the Kingdom was made to be run by Louis XIV. Louis XV wasn't an effective king nor capable of inspiring a national spirit that his grandfather had. The kingdom would fall into debt from the debt incurred from several wars and excessive cost from his lifestyle.

However, it would be the French Revolution that would pull the national identity of France. The Revolution happened and Louis was swept up in it. As a result, the government demanded loyalty of the people not to the King but to the concept of France. It would be here that France emerges as a nation in order to unify the people in order to protect France itself.

This happened in several ways, first and foremost, the army unified the people. Soldiers were no longer raised in regional regiments but in national regiments that were supplied by new recruits. These soldiers would serve with men from all over France, speaking a language that would be similar enough when spoken but not truly the same. Second, the French government would try to rationalize the French language and have every region in France speak and write the same language. Regional variations would make it difficult to govern, so it needed to have the same language. Third, Napoleon brought peace to France and further unified France from the rebelling Vendee and the regions that supported the government in Paris.

It is the Revolution that does the most to create a France that believed in French identity. Other kings helped build a concept that could be French but wasn't universally applied to all the people. The Revolution aimed to make legal equality for all citizens, regardless of location and birth since all citizens were French.