two WW1 subjects : french army cars up to 1918 16 pages , lot of pix including an autochrome , le 370 Filloux (8 pages) and an immediate post-war subject : White TBC armoured cars in "métropole"(6 pages)
Well even if it isn't, pratically every supermarket in France stocks magazines like this. Its definately worth picking up a copy or two if you're on holiday there, they have some fascinating pictures even if you can't speak French. I bought one last summer all about WWI from an Auchen called "Tranchees".
I think I went through a copy of "Tranchées" and my mother in law has a few copies of "14-18" but they are more "public at large" magazines while GBM is more a "researchers" magazine.
You can order them through http://www.histoireetcollections.com/, who also sell the magazine Tank Zone. On their site, you can browse through one or two pages of each article.