I stayed at Sylvain's place for several days with a colleague for a conference. The apartment is on a quiet street within a 5 minute walk to the convention centre (Centre des congrès de Québec) and a 15 minute walk to the old city.
The unit was immaculately clean and provided us with everything we needed. It was a very comfortable stay, and Sylvian was responsive to our questions. There are also some great restaurants nearby, such as Buvette Scott.
Be aware that the staircase to get to the downstairs floor is narrow and spiraled and may be difficult for those with a mobility impairment. We did not have an issue with it though.
Overall, I would highly, highly recommend this apartment as an alternative to expensive hotels in the area. It was perfect! Thank you, Sylvain!