Some time on Saturday morning a car will drive up outside the home of Jean-Francois Menard and a small packet will be handed over.
Long wait: But the French will even consider buying the English version on Saturday
He will thank the delivery-man and repair to his office, where he will unwrap the parcel and - with a deep intake of breath - set to work.
Monsieur Menard is France's Harry Potter supremo. Translator of the first four volumes of the series, he is the man responsible for such coinages as "Poudlard" - for Hogwarts - "Moldus" - for Muggles - and "Nick-Quasi-Sans-Tete" - for Nearly Headless Nick.
Working at the rate of 10 pages a day, he will complete the French version of Harry Potter and the Order of the Phoenix in about 90 working days.
Assuming he has the odd weekend off, that will take him through to mid-October, which allows just six weeks for proof-reading, publication and distribution before French launch day on 3 December.
The books are a phenomenon of modern French society
Sylvie Goffinet, WH Smith, Paris
Much rests on Monsieur Menard.
The French are as crazy as everyone else about Harry Potter - or to phrase it in the vernacular - 'Arree Pottaire. More than 12 million copies of the first four books have been sold here, and anticipation for the fifth is at fever-pitch.
"On the fan-club chat forums there are essentially two messages," says Marie Leroy-Lena of the publisher Gallimard.
"One half are asking how can we get hold of the book in English, and the other half are imploring: please don't tell us the story - we want it to be a surprise in December!"
At WH Smith in central Paris - the capital's biggest English language bookshop - an evening of wizardry is planned for Friday, with readings from the Harry Potter books and performing magicians, before the book goes on sale at 0101 BST (midnight in the UK).
There are 766 pages for Monsieur Menard to translate
"The books are a phenomenon of modern French society. A lot of fans are not going to be able to wait till December, so we are predicting big sales to French-speakers as well as to expatriate British and Americans," says store manager Sylvie Goffinet.
WH Smith plans to have 3,000 in stock for the launch, of which more than 500 have been reserved.
Far from pooh-poohing the books - as it might have done - as a mass-marketed Anglo-Saxon hype, France's intellectual establishment has in general embraced Pottermania.
The books of JK Rowling are novels of initiation for a generation without moral bearings
Psychoanalyst Anne-Cecile Sanchez
This is for the good reason that here as elsewhere it has worked wonders on reading levels. (The French are as paranoid about declining standards as the British).
While teachers swear by it, the left bank "pointy-heads" explore its inner meaning.
"The books of JK Rowling are the transposition into a world of fantasy of the problems of adolescence. They are novels of initiation for a generation without moral bearings," writes psychoanalyst Anne-Cecile Sanchez.
"They are above all about metamorphosis, and what is adolescence if not a period when the human body undergoes the effects of change?"
Readers might argue that the books are actually just cracking stories.
As for the plot of number five, French Potter experts have gleaned as little as anyone else from the internet.
In other words they know that is supposed to be more complex than the previous volumes, that a teenage Harry has some kind of romantic encounter, and that Professor Dumbledore tells him a deep secret about himself.
But beyond that - unless they read English or are called Jean-Francois Menard - they will have to wait to December to find out.