In his long study, Nikolai Zak, researcher in mathematics at Moscow university has put forward several arguments to prove that Jeanne Calment wasn't the world's oldest woman, who died at the age of 122.
Zak, supported by the gerontologist Valeri Novosselov, studied biographies, interviews, photos, the archives from the southern French city of Arles where Calment lived, and testimonials of people who knew her.
His theory establishes that Jeanne Calment died from pleurisy in 1934, instead of her only daughter Yvonne, which was the version of the story at the time.
He believes Yvonne took her mother's identity which allowed her to avoid paying inheritance tax.
Zak also points to discrepancies in the height of Jeanne Calment as an old lady. He cites the 1990 thesis of Doctor Garoyan who studied the evolution of Jeanne Calment's height over a period of time. According to him, at the age of 114, Jeanne was 1,50m which was only two centimetres less than her height at age 57. This is strange because according to him on average, at 80, women have lost around six centimetres in height.
There is also the argument of Jeanne's identity card which states she has black eyes which did not correspond to her eye colour later in life. There appears to be a discrepancy concerning the size of her forehead and chin.
Findings divide scientists and spark debate
On Monday, Nicolas Brouard, research director at France's National Demographics studies Institute (INED) says that part of the research community is "in favour of exhuming the bodies of Jeanne and Yvonne Calment" based on the strength of the arguments in Zak's study.
Interviewed by Le Parisien newspaper in December, Jean-Marie Robine, research director at the National Institute for Health and Medical research (Inserm) refuted the Russian's findings calling the idea of an identity swap ridiculous and not based on anything substantial.
In the 1990s, it Robine and another scientist who validated Jeanne Calment's record as humanity's oldest person.
"We had information that only she (Jeanne) could have known, such as the name of her maths teachers or the housekeepers in her building at the time. We asked her questions. Either she couldn't remember or she answered correctly, but her daughter couldn't have known that."