In reply to Slarti B:
Rings a bell! Or was it Ariege?
Anyway, yes the section up to where it splits from the Madier was bolted, the next bit (Berthet) was trad, after that it seemed to vary at random! We followed the Boell (apparently lots of people take a more direct route up the arete, but we weren't sure where that went), which was very sparsely bolted. The Stoffer near the top had a couple of rusty pegs, though there was a harder-looking bolt line just to the right.
It's a fantastic route, seems impossible from the bottom that there could be an easyish line up there. We had to queue at the start (the weather meant we were there on Saturday) but everyone in front of us and behind us) did the Madier, so we were on our own until near the top, where we shared a belay with the other route so had to wait again.