First raised 1563, the Gardes had precedence over all line regiments and the Gardes Suisses. Recruits all had to be native Frenchmen. It consisted of 6 battalions each of around 790 officers and men. The regiment guarded the outside of any palace in which the king was living. Its most famous action was Fontenoy 1745, where reputedly the British were given first shot and 400 of the Garde were lost to the first British volley. Its most infamous action was to be one of the first units to go over to the Revolution in 1789, despite its privileges and status. The regiment was disbanded at the end of July 1789.
In the SYW the regiment mostly guarded the coasts of France for the first four years of the war. In 1760 four battalions reinforced the army of the Duc de Broglie in Germany. They were at Schaffhausen and Vellinghausen and the siege of Meppen in 1761 but returned to France in October. In 1762 they were back in Germany and were at Grumberg and Johannisberg.
Pierre Charrié (Drapeaux et Étendards du Roi) says that by the late 1760s there were 18 fleurs de lys in each quarter of the ordonnance flag and that at the beginning of the 18th century there were 41 fleurs de lys in each quarter. Interestingly, he shows an illustration of an event at the start of the reign of Louis XV in 1715 which seems to be contemporary and shows the ordonnance flag of the Gardes Françaises with what appear to be only 18 fleurs de lys in each quarter even at that early date.
And here is the 1757 MS depiction of both flags and uniforms:
