Fils de France (French pronunciation: [fis də fʁɑ̃s], Son of France) was the style and rank held by the sons of the kings and dauphins of France. A daughter was known as a fille de France (French pronunciation: [fij də fʁɑ̃s], Daughter of France).
The children of the dauphin (a title reserved for the king's heir apparent, whether son, grandson or great-grandson of the monarch) were accorded the same style and status as if they were the king's children instead of his grandchildren or great-grandchildren.[1]