Régiment du Roi (King's Regiment) was a name given to several of the most prestigious regiments of the French Army under the ancien Régime and Bourbon Restoration, with most of the Army's branches having a régiment du Roi. It is not to be confused with the term régiment royal (meaning a regiment belonging to the king as opposed to régiments de gentilhomme belonging to nobles)
Read more about Régiment Du Roi: Infantry