A rare carbon typescript of Antoine de Saint-Exupéry’s Le Petit Prince featuring extensive handwritten corrections by the author is going up for sale. It is one of only three known copies and marks the first time a typescript of the classic story has been offered for public sale.

The artefact features what is believed to be the first written appearance of the famous lines: “On ne voit bien qu’avec le cœur. L’essentiel est invisible pour les yeux,” translated to mean: “It is only with the heart that one can see rightly. What is essential is invisible to the eye.”

In previous drafts, Saint-Exupéry had been “toying with and turning this phrase back and forward in his head,” explains Sammy Jay, senior literature specialist at London-based book dealer Peter Harrington. In the typescript, “you can actually witness the author making that breakthrough and writing that full sentence for the first time.”

The typescript is priced at $1.25m. It will be showcased at Abu Dhabi Art, an annual art fair taking place at the end of November.

Le Petit Prince was published in the US in 1943 in French and English – with the title The Little Prince – and in France in 1946. Aside from religious texts, it is the most translated book in the world.

The story is narrated by a pilot who meets the little prince who, it emerges, has come to Earth from a faraway planet, where his only friend was a rose. Saint-Exupéry wrote it in New York while in exile from occupied France.

Accompanying the volume are two loose original pencil sketches of the prince, including a preliminary design for the book’s final illustration of the prince returning home, and a cheque signed by Saint-Exupéry.

Peter Harrington acquired the typescript from a privately owned collection of materials related to Saint-Exupéry. The typescript is “a really evocative object”, despite the fact that it seems “unevocative” on the outside, says Jay. It is contained in a black card folder with nothing on the cover and stapled together in places – a “wonderfully makeshift object in a way”. The insides of the folder are “rather endearingly” filled with doodles, notes and sketches.

One of the other carbon copies of the typescript is in the Harry Ransom Center in Austin, Texas, while the other can be found in the Paris’s Bibliothèque nationale de France. The version up for sale appears to be the only one Saint-Exupéry kept as his own working copy.

“He’s filled the typewritten text with his own handwritten annotations, corrections, additions, towards perfecting and finalising the text,” says Jay. Most of the pages have hand corrections; among the changes is the removal of references to New York, which were replaced with more universal imagery.

The $100 cheque included in the package was probably added to the folder by the collector, says Jay. Written on 26 February 1943, it is made out to “Brooks Uniform Co” for an “approximation of a French air force uniform” he had ordered, according to biographer Stacy Schiff.

He wore the uniform the last time he visited his lover Silvia Hamilton’s apartment before heading back to war. On that occasion, he left her the original handwritten manuscript of Le Petit Prince, which is now kept in the Morgan library in New York. He left the US in April 1943 and is believed to have died during a reconnaissance mission in July 1944.