The underlying argument in that article is that the people around Calment would have known that Yvonne is not Jeanne, and therefore they would have been caught.
An alternative explanation is that the people around Calment knew nothing of her claiming to be Jeanne at all until much later on in her life. By which time the only people who knew about the fraudulent claim would be either very old themselves, or sympathetic to the situation an old and dear friend or family member has found themselves in.
The only way to know for sure would be DNA testing.
This doesn't make sense - there is witness testimony and other records attesting that Yvonne, the daughter, died. Her husband sought leave from the military to be by her side.
>It is not reasonable to claim that she could provide, for example, the names of JC’s godparents based upon her recollection of what she might have read many years previously in an attempt to maintain a fraud.
Yes, it is. That's the best example?
> On a eu accès à des informations qu'elle seule pouvait connaître, comme le nom de ses professeurs de mathématiques ou de bonnes passées par l'immeuble. On lui a posé des questions sur ces sujets. Soit elle ne se souvenait plus, soit elle a répondu juste. Sa fille n'aurait pas pu savoir ça.
"We have had access to information that only she [Jeanne] could have known, such as the name of her math teachers or of nannys who passed through the building. We have asked her questions on such subjects. She either didn't remember them, or she answered correctly. Her daughter [Yvonne] wouldn't have had how to know these things."
Things like math teachers' names and nannys seem much more convincing to me. It's not impossible to know them, but I can tell you for sure I don't know such things about my mother, and I am about the age Yvonne was when she died (or when her mother would have died if we believe this theory).
[0] https://www.leparisien.fr/societe/jeanne-calment-une-impostu...