Thanks for your posts!
The fact is that Osos suggested a price which is twice the one that Honey suggested. By the way, it gives me an approximative idea. I am not looking for something very luxuous (my trip is not a holiday trip), nor am i looking for something indecent. Just the middle. Of course, I would be happy to live in a luxuous appartment (if my financial means enable me to do so :) Anyway, I will try to review my budget.
Some more questions: The company i will be making the training in is located at the city center. And it will be great if i can live not far from it. So, I want to know if it is easy to find something in the city center (I live in France and here, it is more difficult and expensive as well). I imagine it should be the same thing in Doha? Anyway, maybe it's the opposite, you never know!
Can you also give me an approximation of the amount of money i will need per month in order to live decently?

Thanks in advance,
cheers!!