Quebec City is good for a day trip if you're living or visiting Montreal. Luckily it's only a 2.5 hour drive away. It's definitely not worth spending more than a few hours there.
The tourist area, Old Quebec, is similar to Old Montreal with cobblestone streets and a Europeanish vibe. Most of the street vendors and restaurant staff speak English since they deal with alot of tourists from other provinces and New England.
I don't recommend the rest of the city though, it's really boring, nobody speaks English, and it's

.