AIUI the Quebecois understand Metropolitan French (from movies, literature, etc.), it's just not what they actually speak. Canadian and Cajun French, again AIUI, are mostly derivative from Norman and Breton, which were never really the same as Parisian, and the emigrants who defined the language left before the French state was able to force Parisian language onto everyone in the country. It's not as far removed as, say, Provencal (which is in some respects closer to Catalan), but definitely not the same as Parisian, and they've had centuries of isolation from the developments in the mother country, during which they've been exposed to a torrent of English (and American English at that; don't @ me, Canadians, we speak the same English and it's distinctly not British, ANZ, or Indian, even if we spell and pronounce a few things differently).