Hello ccj,
in French Army, the ranks are :
1/ soldat de 1ère classe

ne stripe (blue or red, it depends) = lance corporal or private 1st class
2/ caporal ou brigadier : deux stripes (blue or red, it depends) = corporal
3/ caporal-chef : three stripes (2 blue or red and one yellow) = chief corporal (it didn't exit during WW1)
4/ brigadier-chef : three stripes (2 blue or red and one white) = chief brigadier (brigadier = corporal) (ir didn't exist during WW1)
5/ sergent : one single yellow stripe = sergeant (young NCO)
6/ sergent : one yellow stripe with another fine yellow stripe = sergeant (old NCO)
7/ maréchal des logis : one single silver stripe = sergeant (young NCO)
8/ maréchal des logis : one silver stripe with another fine silver stripe = sergeant (old NCO)
9/ sergent-chef : three yellow stripes = warrant officer class 3 or flight sergeant or staff sergeant
10/ maréchal des logis-chef : three silver stripes = WO3 or flight sergeant or staff sergeant
-------------------------------------------
In cavalry, Artillery and Gendarmerie, a sergeant is named maréchal des logis and a corporal is named brigadier (silver stripes instead yellow stripes). It's the same function.
Ludo