Hi again, Paul!
In my view this is a knapweed fritillary, which is a very variable butterfly and so often does not resemble precisely the particular pictures in books. There are lots of individual features that point to this, including the prominent submarginal lunules in s3 of the forewing, with a 'shadow' below and the discal spotting on the hindwing; but above all, this butterfly is clearly reticulate in its overall pattern. Lesser spotted (which would be a bit of a coup in the French Alps, as you know!!) is blotchy.
The knapweed fritillary below was photographed in the Swiss Alps and is rather similar in hue to yours, though the markings are much heavier. Unfortunately, the hindwing is not visible.
Guy