In reply to Franco C:
You come up from the bottom, from the Mer de Glace. I haven't done the Fou but we had a go at the Point Lepiney many moons ago. On my photo gallery the snap of me sitting in the door of the Tour Rouge bivy hut is up that way. The hut's gone but the platform must still be there.
As for gear there was very little on the route we tried, and failed on as we couldn't find the route after a bit. The Fou is harder apparently. Before you head up check out the way back down, we didn't and if we had got to the top we discovered later on that there are no simple ways down. As they are South facing water may be a problem too. Either of these two climbs would be pretty good value though, the rock is splendid.