This catalogue of ‘Le Chemineau’ bicycles does not carry any obvious date. However it mentions the Circuit des Champs de Bataille, a stage race held in 1919 around some of the most gruesome of the First World War battlefields, and the Circuit des Vosges reliability trial of 1920. It also refers to a host of other achievements - that I feel I should be able to date - but I have failed to do so. My guess is that it dates from 1921.
The derailleurs are shown fitted to a bike on scan 6 and in some detail on scan 7. Unlike the earlier (and quirkier) designs from the likes of Terrot, these are clearly recognisable as forebears of the modern derailleur.
Note that both the image of the complete bicycle and the close up picture of the drive chain show a 6 speed set up, with a 44/30T double chainwheel and a three speed freewheel. There doesn’t seem to be a front derailleur - you seem to stop and move the chain by hand. White gloves not recommended.
Finally it is notable that a derailleur bicycle with a ‘ladies’ open frame is explicitly offered. Cycle Touring was an activity for both sexes from the very beginning.