This estimate will probably be exceeded. Previous sales of such 17th-century copies of the Mona Lisa have fetched as much as US$1.7 million ($A2.19 million), as one version did in New York in March 2019.

The 500th anniversary of Leonardo's death was celebrated in 2019 with several prestigious exhibitions, so arguably the market for Leonardo images was at a fever pitch. However, the Mona Lisa, either as an original or through its numerous copies, means money at any time.

Of the many versions of the painting, few copies have a more fascinating history than the Hekking Mona Lisa. It offers a brilliant insight into changing attitudes over the centuries towards the perceived value of originality versus imitation.

None of Leonardo's works is more desirable than the Mona Lisa, which became the subject of arguably the most infamous of 20th-century art heists. In August 1911, Louvre employee Vincenzo Perugia stole the Mona Lisa. The painting was missing for two years before its recovery in Florence and its eventual return to the Louvre in 1913 after a triumphant tour of Italian museums.

The theft made papers all over the world and contributed exponentially to the painting's fame.

In January 1963, amid much international attention, the Mona Lisa travelled to the United States and was shown to much acclaim in Washington DC and New York City. First Lady Jackie Kennedy had brokered the deal in 1961 and media attention on the Mona Lisa in the lead-up to its tour of America reached fever pitch.

It was in the middle of this that Raymond Hekking made the sensational claim that the Mona Lisa that the Louvre was preparing to send to America was not the original - but his was.

Hekking acquired his version of the Mona Lisa in the late 1950s from an art dealer in Nice, France, for around £3. He argued that the copy returned to the Louvre in 1913 was just another contemporary copy of the Mona Lisa.

Hekking turned out to be a genius communicator and masterminded an astonishingly prominent media campaign to get his Mona Lisa recognised as "THE" Mona Lisa. He invited the media to scrutinise his copy and even produced a film to support his claim.

Hekking's attempts to authenticate his version as the "real" Mona Lisa have since been disproved. His painting has been conclusively dated to the early 17th-century and attributed to an anonymous "Italian follower of Leonardo".

All of this raises the question of where the value of an image lies anyway.

For collectors during the early modern period (around 1500-1800), the value of an artefact did not necessarily lie in the fact that the artist made the image themselves. Rather they valued having a copy of an iconic image.

It's important to remember that historically there were fewer images and they were less readily accessible. Seeing an artwork may have required travel to the place where it was kept, and access to the image may have depended on the owner permitting you entry. Ownership of even a copy of a coveted image meant status and privilege and conferred significant cultural kudos on the collector.

Many artefacts were produced in workshops with the help of multiple assistants (rather than by a single artist) but this mattered little. It is quite helpful to think of those workshops in the same way as we would think of a designer's studio today. Works coming from that studio carry the brand of the artist but may not necessarily have been designed, created or executed by the hand of the master.

And still, it's worth being associated with the brand because the imprint of and association with the artist is what matters and what gave value to the owner of the artefact. This is especially so when the creation of multiples meant copying by hand, producing versions that were each unique in their own right.

But now we live in an age where we can all see any artwork reproduced online or through techniques like photography, screen printing or engraving, does that decrease the value of a copy or reproduction?

The German philosopher Walter Benjamin was the first to try and unpick these debates. In his article The Work of Art in the Age of Mechanical Reproduction, Benjamin made the point that an original artwork possesses an irreproducible and inimitable "aura" of uniqueness, which is not present in a mechanical reproduction and therefore reduces its value.

But he also emphasised that any artwork has "artistic authenticity" because it reflects the intentions of the patron who wanted to possess the image and the role of the artist who made it.

There's more then to the Hekking Mona Lisa than being just another Leonardo copy. It is not a mechanical reproduction but an authentic 17th-century copy of an iconic image, and it has spades of cultural authority and stories of its own. If there ever has been an image that invites debates about the value of copies, and reflections about authenticity, they are encapsulated by this famous fake.