Somebody pointed out quite correctly over in the Flyer forum that most pilots flying in the French Alps do indeed seem to use a road map of the area for flying. The road maps have all the topographical information you need as well as showing the roads (funnily enough) which are quite handy for navigation round there! Having flown around the area a bit last year I can attest to this, and invested in a road map of the appropriate scale myself for that very purpose. Naturally, the aeronautical chart needs to be somewhere to hand as well! I went flying with a local from Megeve and was initially quite surprised when he pulled out his Michelin map.
Graham