Excellent find Arthur! I completely agree with your arguments. Left: Connaissance des Arts picture, right: Romanian auction picture
I think it’s a match! Of course the perspective of the two photos differs, but the details of the tiara seem to match absolutely.
left: French auction picture, right: Connaissance des Arts picture
Definitely no match, if you ask me. Especially the shape and setting of small spikes differs. On the left they graduate from very large to really very tiny, on the right they graduate from large to slightly smaller, and they are set more closely together.