While I'm waiting for bits to arrive, I did some research on this model.
Despite people claiming that this was a fairly mediocre bike because of tubing choice, it is apparent it's purpose was to celebrate a major milestone, 100 years, with french steel and french components.
Their line up used various steel tubing at this point and would have been a finger snap to choose premium tubing.
However, it may be the case where the premium tubing was hard to work with/too expensive, considering the design of the tube profiles used.
If carbolite is seamed tubing it would have been easier/cheaper to manufacture.
This is as far as I managed to get. If anyone knows more and would like to chip in, is more than welcome.