We stayed at Souzana's apartment while passing through Thessaloniki and would recommend it for anyone looking to stay in the city. It's situated in a charming meideval neighbourhood near the city centre, on a hill slope with small winding roads, hidden stairways and old buildings. There's even a street 2 minutes from the apartment with great restaurants and a local atmosphere, for those who don't enjoy the more touristic city centre.
The parking space in in an underground car park next to the building entrance, extremely useful in an area with such small roads. It may be difficult to park for less experienced drivers (also watch out for the narrow streets and very steep slopes) but definetly doable. The garage door height is quite low, so watch out if you have a car top carrier (we narrowly got in with a VW Golf with a regular sized Thule carrier).
Souzana was very helpful with the instructions, recommendations and whatever else we needed. Will defiently go again if we get the chance.