The Celine is a well-kept converted Ottoman property located in a very nice central location, close to historical places and public transportation, We stayed here twice over the past month on our Istanbul to Athens and back to Istanbul legs o our trip.
It is a small property, so the staff gives you a very personalized experience. I can't say enough about the Manager of the property Nezvat who was very helpful in helping us with anything we needed during both our stays. We stayed in a room in the front which could get a little noisy if you are jet lagged so at our request we got another excellent room overlooking the Bosphorus Straits. The rooms are spacious and very clean and well equipped. The breakfast is very hearty and the young man (forget his name) made me one of the finest cups of Americano coffee. The breakfast selection is also good.
The Blue Mosque, Hagia Sophia, and Topkapi Palace are all within walking distance and so also is the trolley. You can buy a Turkey Kart or multiple trips and buy the card at the Sultanahmet station nearby. Nevzat and other hotel staff helped book fixed rate cabs to and from the airport and the fare is 1,000 Turkish liras. If I visit Istanbul again, will definitely stay at Celine Hotel again.