Nikos was very kind, he also agreed to meet with us on the Aristotelous parking lot so we could easily go to the apartment. The stay was super nice, the place is clean and cosy. It's a little bit further from the city center ( around 5-6km ), but you have the bus that goes directly to the Aristotelous square, it takes around 30 min to get there, and the bus station is 100m from Nikos place. If you have the car then it's about 10-15min MAX.
I would recommend Nikos place to everyone who would love to visit Thessaloniki. :)