You will need a good map for your trip to Mont Blanc. I recommend one of the following two:
They cover somewhat different areas, but both comprise the terrain in question here, and in my opinion they are equally well suited for this trip.
The maps are most conveniently bought in Chamonix or Les Houches when you get there. Most local bookstores there carry them.
They are published by:
Institut Géographique National (IGN)
107, rue de la Boétie
To assist your planning, I have scanned two A4 excerpts of the 3531
map and put them up for download, Bast protect me from the wrath of the
Here they are:
Additionally, the original TIFF- and PNM-files from the scans are available, in case the above JPEGs don't give you sufficient detail. But these are monstrous in size, and therefore gzipped:
Please note: These map scans are provided for planning purposes only. If you make paper copies from the scans, the scale will most likely be quite incorrect, and (maybe important) details are bound to have been lost either during my scan or your printout. You must buy the map! They are not expensive, including inflation since I bought mine I would estimate about 80 FFR.