Make full use of the 6h55min in Istanbul

Hello guys! I'm going to take a flight from beijing to paris, with a 6h55min layover in Itanbul. Since i'm always intersted in the famous city, how can i make full use of this 6h55min stay? I‘m not familiar with the practical staff in Istanbul pretty much, not at all precisely. Is it safe for me to hang around in the centre of Istanbul during the "dangreous" interval?(free from visa worries). btw this is my first time going aboard an totally on my own.