All smiles: Carla Bruni has described her marriage to French President Nicolas Sarkozy as a "fairytale"
By Hugh Schofield
BBC News, Paris
French police have launched a criminal inquiry to trace the bloggers behind rumours President Nicolas Sarkozy and his wife were both having affairs.
The inquiry follows a legal complaint filed by the Journal du Dimanche newspaper.
It was on a blog housed by the paper's website that the speculation about the Sarkozy-Bruni marriage first appeared in March.
The rumours, relayed around the world, then appeared on newspaper front-pages.
However it now appears that they were based on no more than idle fantasy.
Two employees of the company that runs the newspaper's website have since resigned as a result of the scandal.
One of them admitted having posted the rumour - though not having started it.
News of the police investigation - technically into "introduction of fraudulent information into a computer system" - follows an angry outburst over the weekend by President Sarkozy's media adviser Pierre Charon.
He said it was time for "fear to change sides" in the confrontation between gossip-mongers and the Elysee Palace, and aired the suggestion that the latest rumours may have been a deliberate plot to destabilise the presidency.
The media has a seemingly endless appetite for the glamorous couple
Mr Charon denied that the Elysee was behind the newspaper's decision to lodge a legal complaint, though he said he welcomed the move.
However, several newspapers have said that Mr Sarkozy actively encouraged the Journal Du Dimanche (JDD) to launch proceedings.
They note that the president is close friends with Arnaud Lagardere, the millionaire businessman who owns the JDD.
Claims that the infidelity rumours might have been part of a deliberate machination were further echoed on Monday by Mr Sarkozy's lawyer, Thierry Herzog.
He said it was suspicious that gossip targeting both Mr Sarkozy and his wife should have emerged simultaneously.
The original reports said that Mr Sarkozy was having an affair with Ecology Minister Chantal Jouanno, while Carla Bruni was seeing the singer Benjamin Biolay.
"[This] suggests that the rumours are certainly not neutral and that someone is behind them," he said.
"The police inquiry will establish if those who spread the rumours did it on their own account, or were instrumentalised by groups or individuals," he said.
In his remarks to the Rue89 news website, Mr Charon said that the rumours could have been aimed at harming French standing in the world - even implying that international banks could be seeking to speculate against French assets.
The couple were married months after they reportedly first met
"Now [with the police inquiry] we'll find out if there's been some sort of organised conspiracy - with financial movements, why not?" he said.
"We are going to make this disgrace a casus belli [a reason to go to war]. We're going to do all it takes to make sure it does not happen again. Fear has got to change sides," he said.
Mr Charon's comments were condemned by the journalists' union at the JDD, which said they "sounded like a threat".
Noting that the newspaper's editor has already apologised for the affair - and that two people have been sacked - the union said: "Just like any other media, the JDD cannot bend to the will of the powers-that-be, nor give way to pressure or threats, wherever they come from".
The salacious coverage given to the rumours in the international press has certainly shocked many in France - especially given the total lack of evidence that was produced in support.
However, not for the first time the Elysee stands accused of over-reacting - and risking much of the sympathy it might otherwise have enjoyed.
Meanwhile Rachida Dati - the former justice minister and one-time Sarkozy favourite - has vehemently denied allegations that she was behind the love affair rumours.
"It is unthinkable that Madame Dati could have helped destabilise a president to whom she owes so much - perhaps everything - and to whom she also remains deeply attached," her lawyer Georges Kiejman said.