Hi Tunisian
I've just relocated in Qatar and i dealt with a very good real estate company that didnt charge me any thing although they were my consultants and got me what i was searching for before i land , the company called Retaj their tel. is 4995555 and i deal with someone called wael he was lebanees i think , you can call them and ask and i think they will tell you the best you can go for , and its a free consultation ;)
Good luck