Maître de camp was a rank in the Ancien Régime French army equivalent to Colonel

Colonel

Colonel , abbreviated Col or COL, is a military rank of a senior commissioned officer. It or a corresponding rank exists in most armies and in many air forces; the naval equivalent rank is generally "Captain". It is also used in some police forces and other paramilitary rank structures...

. A maître de camp commanded a regiment. A regiment's commander was initially called a Colonel from the time of Francis I

Francis I of France

Francis I was King of France from 1515 until his death. During his reign, huge cultural changes took place in France and he has been called France's original Renaissance monarch...

 to that of Henry II

Henry II of France

Henry II was King of France from 31 March 1547 until his death in 1559.-Early years:Henry was born in the royal Château de Saint-Germain-en-Laye, near Paris, the son of Francis I and Claude, Duchess of Brittany .His father was captured at the Battle of Pavia in 1525 by his sworn enemy,...

, then a Mestre de camp

Mestre de camp

Mestre de camp was a military rank in the Ancien Régime of France, equivalent to colonel. A mestre de camp commanded a regiment and was under the authority of a Colonel General, who commanded all the regiments in one "arme"...

from then until 1661, after which the name of the rank was repeatedly changed. Colonel was used whenever the rank of Colonel général

Colonel General (France)

A Colonel General was an officer of the French army during the Ancien Régime, Napoleonic era and the Bourbon Restoration.The positions were not military ranks, but rather offices of the crown. The position was first created under François I. The Colonels General served directly below the Marshals...

 (commander in chief of all the regiments in an army) was out of use or suppressed. When colonel général was revived, so was colonel or maître de camp.

The rank of Maître de camp général also existed, equivalent to Colonel General

Colonel General (France)

A Colonel General was an officer of the French army during the Ancien Régime, Napoleonic era and the Bourbon Restoration.The positions were not military ranks, but rather offices of the crown. The position was first created under François I. The Colonels General served directly below the Marshals...

.

Source

• Julian Corbett, The Colonel and his Command, The American Historical Review
  American Historical Review
  The American Historical Review is the official publication of the American Historical Association, established in 1895 "for the promotion of historical studies, the collection and preservation of historical documents and artifacts, and the dissemination of historical research." It targets readers...
  
  , Vol. 2, No. 1. (Oct., 1896), pp. 6–7]