Thanks a lot Eda and Neyzen, we enjoyed so much our stay in Istanbul :)
The apartment was really great, very cosy, clean and confy. We just felt like home ! It's perfectly located (Good bars/restaurants at walking distance). Everything you need is in the apartment. The decoration is very cool.
Bonus : Amazing view on the city (ok to enjoy it, you have to climb 5 floors, but it really worth it!!)
Neyzen was out of town, but Eda, his friend, took in charge of everything. She was very helpful and very kind, and easy to reach. Again : THANK YOU !! I hope I'll come back soon !