He resigned his commission in 1906, as he was banned from achieving higher rank due to his controversial father-in-law and by his strong nationalist and Catholic sentiments.

In 1888 Driant began writing his first guerre imaginaire ("imaginary war") novel, which he was to publish using the pseudonym "Capitaine Danrit".

The action begins with La Guerre en fortresse, as reports arrive of a surprise German attack upon France.

He published so much fiction, and his stories were so long, that half a century later Pierre Versins said in his Encyclopédie de l'utopie et de la science fiction (1972) that the hundred pages of Chesney's Battle of Dorking were much more important and revealing "than the thousands of white pages soiled day after day by a national hero of France" (Driant had a postage stamp dedicated to him in 1956, Scott #788,[1] Yvert et Tellier #1052).

In December 1915, he criticised Joseph Joffre for removing artillery guns and infantry from fortresses around Toul and Verdun in order to strengthen other areas of the now-deadlocked Western Front.

Driant was proved right on 21 February 1916, when the German Army initiated a massive attack on French forces in the Verdun sector.