Well thank you all for all your comments!
I think that it is strange to calculate the landing field length with precise inputs and complicated garaphics (in Dassault's AFM) and disregard such an important factor like the temperature! It might have a historical reason but it still doesn't make much sense just multiplying this inprecision with a factor of 1.67 or 1.92 to operate safely.
So operators in cold countries are safer than the ones flying in warm countries??