In reply to Ilya:
I’ve gone to Chamonix a number of times just to Boulder. You should mostly be ok as there’s a fair amount down in the valley
There are extensive Font style colour circuits in the woods near the Bossons glacier. They’ll need a good brushing at that time of year, but they’re easily accessible, near a road and great landings.
There is very good bouldering on both the French and Swiss sides of the Col de Montet above Argentiere, but could be dependent on the weather.
A new find this Summer was slightly down the valley at Meddonnet which has three big sectors. Again, there are Font style colour circuits here in lovely pine woods.
There are circuits in Argentiere, and on the way down to Chamonix at Le Lavancher.
I’ve bouldered there in October and its been ok, but I might have just been lucky with the weather. If you do go, pop into Snell Sports in the Centre and pick up ‘les blocs de la region de Chamonix’ by Emmanuel Ratouis which covers the valley quite well. Again, there is ‘les blocs auteur de Chamonix’ by R Desgranges which is reasonable coverage.
Good luck
paul