The 21e RIC was principally engaged Champagne, on the Somme and the Chemin des Dames and was cited in the Order of the Day four times.

The two fraternal regiments relay equally the duties of services around the respective garrisons in Paris which revolved around: honorary detachments, parades, award of decorations and national funeral procession of Marshals Joseph Joffre and Ferdinand Foch.

Overseas service postings included the Levant, Madagascar, French West Africa, Algeria, Morocco, China, and missions alongside the Czechoslovakian and Polish militaries.

The men of the 2nd Battalion under Major Varrier were entrenched in an arc around Villers by 13 June, with the rest of the regiment in a line to their east.

At 1430, two German tanks attempted to infiltrate on the left of the battalion in front of the 7th Company (Captain Allegrini) on the Ante road.

A company, commanded by Captain Marchenoir, of the 18th Light Infantry Battalion of Africa, was made available to Major Varrier on the night of June 13 to 14, to strengthen the western side of Villers.

Enemy aircraft, flying at low altitude, strafed the positions of the 2nd Battalion and the village of Villers during the morning.

German infantry moved behind cover to about 800 m from the village and at 1500, the enemy, singing and shouting, probed the positions of the 2nd Battalion.

At the same time, with artillery support, the Germans pushed through the woods, on the flanks of the battalion, pressing on Captain Allegrini's 7th Company in an attempt to encircle its position.

After the last units passed, Varrier ordered a Lieutenant of Engineers and four men to come with him and blow the bridge over the Aisne, the Pont aux Vendanges between Villers and Passavant.

The 2nd Battalion and the regiment as a whole were disappointed to have given up the ground they had held in the face of serious attack but their continued movements south were necessary to protect and cover the retreat of other units.

For the past 25 years the regiment and its battalions have been widely deployed in the following areas: The 21e RIMa is articulated into eight companies: The anniversary is celebrated for combats in Bazeilles, the village which was apprehended and abandoned four consecutive times under orders, respectively on August 31 and September 1, 1870.

The motto of the 21e RIMa is "Croche et tient" (Fr) which translates to "Hook and apprehend" (Eng) which defines the regiment's conduit to battle.

"Quand l'aventure est un métier" (Fr) which translates "When adventure is a formal job", a slogan picked by colonel F. Loeillet in 1998.