This fine set of instructions is referred on my scan 7 of the ‘Le Chemineau’ catalogue that I have guessed as dating from 1921 - so I will give it the same date.
The gear ratios described are refreshingly wide. The typical three speed system is listed with a 48T single chainwheel and a 14-28T freewheel, while a typical 6 speed systems is listed with a 42/28T chainwheel driving a 14-24T freewheel. None of this would be considered too mad even today.
It’s all very impressive for 1921.