Montreal has many public markets, like Atwater, Maisonneuve or Jean-talon ..
I especially like Jean-talon market, it is full of ambiance especially during the summer, the atmosphere is very good, farmers come here to sell their fruits, vegetables and other home made stuff, every thing is organized in symphony of colors and there are always samples for taste ;))
The area is a multiethnic and it is very present in the market area with the people who come and with the small italian, arab, latin or quebecer groceries. Also what make it nicer, arround the market there are small restaurants and cafes with terrace.
My favorite thing is: eat a merguez or lamb sandwith, some fruit dessert from the market and espresso cafe in the terrace cafe ;)