The unsigned statue, 22.5 centimetres (nine inches) tall, depicts a female figure, standing but stooped as if in pain, with a draped fabric over one arm and clenched between her thighs.
"All the clues point to Rodin," Gilles Perrault, a leading expert on the 19th-century master, told a press conference as he presented a report that purports to authenticate it.
"This statuette was born of unknown parents, but its signature is written in every muscle," he said.
The figurine -- which Perrault has dubbed the "femme meurtrie" or "wounded woman" -- was not displayed for security reasons.
There is no mention of the work in official records, nor in letters between Rodin and his lover -- and the state-owned Rodin Museum in Paris has voiced strong doubts about Perrault's claim.
But after studying the statuette for a quarter-century, Perrault says he is now "intimately convinced" it is by the sculptor, who lived from 1840 to 1917, and that it was created around 1886.
He believes its subject is a reference to Rodin's tortured love affair with Claudel, specifically to several abortions she is believed to have undergone during their time together.
The silver figure carries neither the signature of its creator, nor the hallmark of the foundry where it was cast and polished.
It first surfaced in the 1980s after an antiques dealer spotted it in a Paris flea market, and sold it to its current owner, a private collector, who contacted Perrault to establish its origin.
Himself a sculptor, Perrault is an official expert for France's Cour de Cassation who has carried out more than 750 appraisals connected to Rodin's work. He has worked as head of restoration work for the Louvre and the Chateau de Versailles.
His search sent him digging through the archives of the Rodin Museum and collections in France and abroad, comparing sketches, works and techniques by Rodin and Claudel, even rooting though their foundry receipts.
In particular he focused on the subject's hands -- the spacing between the fingers -- on its highly-stylised feet, and on the folds of the draping, which he argues are typical of Rodin.
"Back then," Perrault explained, "Rodin was at odds with the whole establishment, he was the only sculptor who used fabric covered with plaster or wax."
Analysis uncovered microscopic traces left by the plastered fabric on the statuette, he said, along with minute grooves similar to ones found on a Rodin work in memory of the writer Honore de Balzac.
The woman's heavily stooped back suggests a spinal malformation -- just like the one that afflicted a model who regularly worked for both Rodin and Claudel.
And for Perrault, the woman's posture is "typical of the twist of the body and the tension of the muscles that the artist used so distinctively to express feelings."
"So many clues and coherent facts cannot be an accident," he said.
Perrault draws a distinction between his technical analysis -- which he says establishes the work as Rodin beyond doubt -- and his opinion on the subject depicted, which he admits is biographical speculation.
He believes Rodin meant to show Claudel "wounded, sad, but regathering her strength" after undergoing "one or several abortions".
Rodin had repeatedly promised to wed the young woman, 24 years his junior, but never kept his word.
The Rodin Museum has said it is not convinced by Perrault's case, and declined an invitation to his presentation.
"We are very, very sceptical, in the absence of documents referring to the existence of such a silver statuette, or to any other works that relate to it," said its asset curator Aline Magnien, contacted earlier this week.
"This work has no pedigree," she said. "Gilles Perrault has created a fiction."
Since the sculptor's estate was donated to the French state, the museum today acts as a de facto "guardian of the temple," Perrault said.
"If they have doubts about the work, it is tarnished as a result."