Electrolux had a similar vacmobile in the 20s in Europe.
In US Hoover had a giant Constellation(not a vehicle)for display at dealer conventions.I have seen some evidence that it was later reworked into a giant
Celebrity.
I think it must be French, rather than Canadian, based on what appears to be a long, narrow European style license plate on the back of the one in the foreground.
Most likely France. Hoover Canada would have had bilingual English/French graphics back in those days when Montreal was Canada's largest city. The lack of any English on these promo vehicles makes me pretty sure it's from France.