A row has broken out in France over whether the private lives of public figures should be sacrosanct.
A new book published this week, Nos Delits d'Inities (Our Inside Dealers), argues that French journalists hush up the personal secrets of the elite.
Birenbaum says French journalists are much too timid
Author Guy Birenbaum airs for the first time in print rumours that President Jacques Chirac may have had a love-child with a Japanese woman - and he criticises the French press for never investigating the claim.
However, some mainstream newspapers have called the book a hymn to the excesses of the gutter press.
Perhaps surprisingly for a nation often associated with romance - and which coined the phrase menage-a-trois - France's press has always been prudish about the sexual lives of the high and mighty.
Unlike the British or the American public, the French are spared details of their politicians' infidelities.
No juicy kiss-and-tell book by a former mistress darkens the shelves of French bookstores.
According to Mr Birenbaum, this not because French opinion-makers are a decent, scrupulous lot.
He argues that they are cliquish and arrogant, and summarises their attitude thus:
"We sort out what is good for you and what you need to know," he writes.
"It has been like this for years and there is no reason why it should change."
By printing the rumour that President Chirac had a son, who would now be about 20, with a Japanese interpreter, Mr Birenbaum has certainly broken a taboo.
He gives no evidence for this unsubstantiated claim - but this is part of his point.
Although French journalists in Japan have long known about the rumour, he says, no-one has ever bothered to investigate it.
The French president's press service was unable to comment on the suggestion on Thursday, because his spokesmen were in Germany, leaving only low-ranking assistants behind in Paris.
The French media is reacting to Mr Birenbaum's accusation by holding its collective nose.
The left-wing daily Le Monde accuses Mr Birenbaum of dishing out a mixture stale news and unfounded rumours in an attempt to "confine readers to their own nausea".
The right-of-centre weekly L'Express calls the book a "hymn to baseless denunciation".
"It advocates the dictatorship of the rumour, [by arguing that] it is not necessary to sort out truth from lies, or what is important from what is trivial," the paper writes.
Mr Birenbaum's book, in the end, is unlikely to make a difference.
For better or for worse French journalists will continue to regard the personal affairs of politicians as off limit.
This is due both to France's privacy laws and a time-honoured tradition of journalistic reticence.
The dirt dished by murderer Patrice Alegre was discredited
Even though some journalists appear to have broken the mould in recent years, that tradition it is still holding firm.
When the French public in 1995 learned that Francois Mitterrand had an illegitimate daughter, the "revelation" was printed with the tacit support of the president, and just before he was due to retire from public life.
French journalists, it turned out, had known for years about the child and her mother - who were both living in a flat owned by the state - but had kept the secret.
More recently there was the "Alegre" affair, named after an ex-convict who accused a senior politician of being involved in a tale of sado-masochistic orgies, rape, and murder.
To be sure, French media regaled the public with every sordid detail of the allegations.
But they turned out to be fanciful, and the lesson drawn by a chastised French press was that more, not less, restraint was in order.