The flat is nice (even without washing machine and dryer) and rather well furnished for the small space.
Yet, several difficulties appeared:
1) keys given to someone else before our arrival,
2) still other ones had a duplicate of the keys to the flat during our stay and put it in one of the three lockboxes which serve for "self check in",
3) elevator was not working,
4) the stairway is steep and narrow (and also dirty and smelly) which is a real inconvenience with large suitcases,
5) the hallway was stuffed with material for renovation/repairing work (same inconvenience with large suitcases)
6) the complete floor appears to be rented for short term stays and the many comings and goings (at any time of day and night) are noisy in this context.
When the issues will be fixed, it will be a very pleasant place to stay, close to many nice spots in Montreal.