When in the city, you should definitely consider visiting the historical centre of Quebec. It is the true heart of the city. Among the many things you can see here are the typical stone made houses. It is no surprise this part of the city is on the UNESCO World Heritage list.
The Old Quebec is divided into two parts - the Upper and the Lower Town. Among the most popular sights that you can see here are e.g. the imposing Château Frontenac (which is a grand hotel) or Our Lady of Quebec City Cathedral. You can also try travelling by the lovely Old Quebec Funicular. The whole area is also filled with restaurants, bars and cafés.
Wikipedia https://en.wikipedia.org/wiki/Old_Quebec
Address 51 Rue du Trésor, Québec G1R, Canada
Coordinates 46°48'46.795" N -71°12'22.209" E