If I know you probably live in Montreal, but I want to make sure it’s true, I would ask you:”do you live in Montreal?” Or “Are you living in Montreal?”
In this sample: “Do live in”or “ Are you living in” is same meaning.
But if I meet you in bar for instance and I try to make conversation, I would ask you :” hey ,where do you live?” You probably would answer “I live in Quebec “. In this case I only want to make conversation, and I don’t care more details about the place you live If I want to know more details about the place you live, I would ask:” Where are you living (now)?” You probably would answer “I’m living in Montreal.”