Régiment du Roi was a name given to several of the most prestigious regiments of the French Army

French Army

The French Army, officially the Armée de Terre , is the land-based and largest component of the French Armed Forces.As of 2010, the army employs 123,100 regulars, 18,350 part-time reservists and 7,700 Legionnaires. All soldiers are professionals, following the suspension of conscription, voted in...

 under the ancien Régime and Bourbon Restoration

Bourbon Restoration

The Bourbon Restoration is the name given to the period following the successive events of the French Revolution , the end of the First Republic , and then the forcible end of the First French Empire under Napoleon  – when a coalition of European powers restored by arms the monarchy to the...

, 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)

Infantry

In 1663, the régiment Royal Infanterie was renamed the King's infantry regiment. In 1791, it became the 105e régiment d'infanterie de ligne.
In 1814, the 1st Infantry Regiment was renamed régiment du roi; it lost that name in 1816.

Light infantry

In 1814, the 1st regiment of light infantry regiment was renamed régiment du roi. It was reformed in 1815.