if you want to have a quiet and relaxing stay at Athens while being close to the center..look no more as Oltian place will do the job, the studio apartment was clean and comfy with all the basic necessaties! Just 10 min walk to Monestraki square. Moreover, Oltian is a fast communicator and he prepared a detailed guide that you won't even need anything.
Just wanted to clarify regarding the negative comments of the neighborhood, basically the building is located in a neighborhood where most of the occupants are immigrants (Indians, Chinese, Bangladesh, Arabs, Africans..etc) consequently the government doesn't give much attention in regards to servicing/maintenance as opposed to neighborhoods where the locals stay. Nevertheless this doesn't make it an unsafe place, on the contrary I walked there in the middle of the night and it was just fine. I've traveled to a lot of countries in 4 continents and seen worst places. would definitely stay there again given the chance and would recommend.