According to Turkish Laws, a
preliminary contract for real estate sale can be valid only if it is arranged and signed before a notary public (except some very very rare exceptions). For this reason, any contract or document regarding the sale of a real estate, which you sign in a real estate office or with seller or buyer in Turkey will not be legally valid. In the case of a conflict, such a document will not help you properly. Be careful. Err on the side of caution!