Why a prisoner of war doesn’t appear in your archives ?

Filae digitized and indexed 2 sources about prisoners of war :

French soldiers prisoners 14-18 : The german authorities decide to use the Ardennes Gazette, for propaganda purposes : it’s to knock out the french public opinion by the masse of captives, but also to give a respectable image by treating her prisoners well. From spring 1915, the Gazette published list of french prisoner, whose publication date often differs by several month from the date of captivity. From 1916, those lists included prisoners from the Bulgarian and Austrian fronts, those from the Dardanelles battle, repatriations for health reasons, prisoner exchnages and transfers to Switzerland.
French soldiers prisoners 39-45 : At the request of the French authorities, to informe families about the fate of their captive parent, the Reich authorities transmit the information allowing to publish offiicial lists of prisoners. There will be 100 published between august 1940 and june 1941. The official list of war prisoners published by the National Center of Information about the war prisoners.

We are at war and the information travel with difficulties, which leads to oversight. Prisoners might not be present in those lists.

You may find information in the following archives :

Don’t forget the military registers might give you some information. They are generally not digitized after 1921 and must be consulted in the departmental archives