Having a separate language and a more insulated stand-alone culture and media helps to shelter the market a little. Montreal specifically has something of a left, lots of students and broke artsy fartsy anglophones, and a dedicated activist core. I wouldn't be surprised if that helps a little.

Quebec City is certainly more conservative but also smaller, more francophone, and maybe a bit more isolated from the rest of the housing market. Idk really, only been there once.