We stayed there for one night following our return from Halkidiki. The flat is in a very central location, but this is probably the main and only positive I'd have to add unfortunately. Location wise it should be noted that there are a number of cafes and bars downstairs which create a noticable level of noise until c. 1am (to be fair it is not unbearable, but definitely more than ideal).
Also, just to highlight for any people that may have missed this (like us) in the description, the flat is on the second floor without any lift access. Entrance and staircase is rather unappealing, but probably this is the least of people's concerns.
The flat overall is in a good condition, but the bathroom is a big disappointment compared to the images provided, and as other reviews have now highlighted, has notable signs of mould above and around the shower.
The communication with the host was far from ideal. We did not receive any communication regarding the check in until we reached out a day before. We were told that we can check in after 3pm the following day and that we would be notified once the cleaning had been completed. We went to the flat at 3pm, even if we had not heard at all by that time, and when we contacted the host we were told that the check in is "anytime after 3pm", implying that it does not necessariliy mean 3pm. Ultimately we wondered around for a bit and at 3.30pm we received a text that we could collect the flat's key.
Lastly, although the flat was equiped in terms of pots and pans etc. there was only 1 capsule for a coffee machine provided. I understand that when you stay just for a night you won't be provided with many "freebies" but just one capsule for two people (and nothing else in the fridge or cupboard) is rather stingy.
Unfortunately, I won't be able to recommend this flat. We also stayed in a different flat for 4 nights before going to Halkidiki (again near Navarinou square and for approximately the same price) and was the complete opposite experience.