France defends status of world's oldest person after claim of fraud

When she died in 1997, Jeanne Calment was the oldest documented person to have lived, at 122.

Now, French officials have moved to pour cold water on a claim from a Russian mathematician that the person who died in 1997 was not Jeanne Calment, but in fact her daughter Yvonne.

The mathematician, Nikolay Zak, claims that Yvonne Calment assumed her mother's identity in a tax avoidance scheme.

But French officials say the claim is a "ridiculous controversy".

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