Having bought a new magnifying glass, I was able to read this. It has very tiny print, continuously
HALFFRANCTOKENNAAFIONLY
on both faces.
It seems to be in bakelite, possibly with a cardboard core, about 24.5mm across.

When were they issued, where were they used, how much is it worth retail, please ?
Are there other denominations to collect ?
Were soldiers expected to read the print, or would they know its denomination by size or colour ?