The Salvator Mundi, an ethereal portrait of Jesus Christ which dates to about 1500
The Salvator Mundi was thought to be painted by Renaissance master Leonardo da Vinci, but doubts have been cast over the painting's authenticity.
The painting, which was unveiled at The National Gallery's 2011 Leonardo exhibition, broke auction records at Christie's in New York, 2017 when it was bought for $450million (£342million).
Christie's confirmed the Abu Dhabi Department of Culture and Tourism was 'acquiring' the painting, but its next unveiling, due to take place at the Louvre Abu Dhabi in September, was cancelled with no explanation.
The Salvator Mundi, which depicts Christ as 'Saviour of the World', is now alleged by some to be a 'workshop Leonardo', painted by one of the artist's studio assistants.
Art historian Jacques Franck told the Sunday Telegraph that senior politicians and Louvre staff 'know that the Salvator Mundi isn't a Leonardo'.
He has reportedly written to French President Emmanuel Macron to warn him against inaugurating the Louvre's Leonardo exhibition this autumn if the allegedly fake painting is included - which would be 'almost scandalous'.
The painting was also said to be facing a snub from the Louvre in Paris, who were reported to have scrapped plans to display the work in its Leonardo da Vinci exhibition.
But a Louvre spokeswoman told MailOnline: 'The Musée du Louvre has asked for the loan of the Salvator Mundi and wishes to present it in its October exhibition.
'We are waiting for the owner’s answer.
'M. Franck was part of the scholars who have been consulted 7 or 8 years ago for the restoration of the Saint Ann.
'He is not currently working on the Leonardo da Vinci exhibition and has never been curator for the Louvre.
'His opinion is his personal opinion, not the one of the Louvre.'
The painting's appearance has been said to have changed between the time it was unveiled in 2011 and its auctioning off six years later, raising questions over its restoration.
Last August reports emerged that Matthew Landrus, a research fellow at Oxford University's Wolfson College, said the artwork was actually painted by da Vinci's assistant Bernardino Luini.
Reports had suggested that Saudi Crown Prince Mohammed bin Salman was the painting's buyer.
Da Vinci scholar Professor Martin Kemp, who helped authenticate the piece a decade ago, had previously told The Times: 'Nobody outside the immediate Arab hierarchy knows where it is.'
Western diplomats said a Saudi royal acting as a proxy for Saudi Arabia's Crown Prince Mohammed bin Salman was the buyer.
The Saudi Embassy in Washington says the Saudi royal purchased the painting on behalf of the museum in Abu Dhabi.