I haven't seen a lot of discussion of the use of French during the Second World War, but ISTM that Granatstein talked at least a bit about it in some of his writing. My understanding is that there was a real attempt to engage the francophone population, to the extent that official manuals were translated into French. Not all of them, perhaps, but many.
The practice of dual-language manuals as we see them today was not standard until French and English were made the "official languages" - I stand to be corrected here - which I think was one of the Trudeau policies.
But the attempt to engage the francophones went beyond just manuals. Granatstein's book THE GENERALS talked about the attempt to create, for example, an entire French-speaking brigade in one of the overseas divisions, a movement scuppered by the lack of French-speaking staff officers (again, IIRC) and officers with senior command experience. The French-Canadian battalions were split up among the various brigades. As is well known, 5 Brigade was originally to be an all-Quebec brigade (to include the anglo Royal Highlanders from Montreal). Deployments to Iceland and Newfoundland changed up the scheduling, and also the francophone "problem", I believe, caused the Calgary Highlanders to be shifted to this brigade instead.
Terry Copp has written a little on the subject also. I admit to not reading nearly as much on this as I would like, and am not sure what is available in the military journals, etc. but suspect there is much more that could be done - in English - on the subject of the experience of the French-Canadian soldier in the Second World War.
If anyone has any suggestions for further reading on the subject (again, in English), I'd find them most welcome.