[2] During the First World War, Olry served in the Second Army at the Battle of Verdun under the command of then-general Philippe Pétain.

[2] He left for Italy in 1917 as part of the French expeditionary force and participated in combat near the Piave River, and in 1918 assumed command of the 283rd Artillery Regiment.

The performance of the French army in this theatre was far more successful than on the rest of the front and preserved some areas of France from occupation.

He was then appointed to command the 1st Divisional Group of the French Armistice Army: comprising four divisions in the non-occupied south.

In June 1942 he reached retirement age and took up residence on his family estate in the Charente region of Mansle.