Mid-July for the first round..
I have been going to France to ski for the past 9 years.. and snap up tckts when the fares come out..
Generally the first fares have been showing up mid to end of July for cheaper ($400-500) fares.. Then 350-450 Mid september... Real bargains (as cheap as) 275 - 350 just before XMas.. Generally good until about March 15th~ish
If I get lucky, I can get to France to ski, cheaper than DFW-DEN.. The food & wines is a bit better..