Up to a million French people denounced their neighbors to the Nazis during the Second World War, historians have revealed.
© Getty ImagesPower of the community: A French woman who collaborated with German troops is scorned by neighbours in Chartres, 1944
But more betrayals were over petty family and neighbour disputes than accusations of being French Jews.
The findings were aired at the world's first international conference on French denunciation in the Second World War, in Caen.
They challenge some of the popular misconceptions about denunciation in wartime France.
Historians now say only a very small percentage related to Jews and a large proportion - around a quarter - of the letters were about French family dramas often involving husbands, wives, lovers and village rivals.
"Denunciation was a very easy way of getting rid of someone," said Laurent Joly, the historian who organised the conference.
He cited the example of a father who opposed his daughter's preferred suitor, so he sent his name to the Gestapo.
"A case that I have seen crop up quite a lot is the prisoner of war who returns home to a wife who has a lover. To get him out of the way, the lovers then accuse the cuckolded husband of hiding a weapon in the house and denounce him," he said.
However, the Nazis examined these cases carefully and did not appreciate being taken for a ride.
"In one case they realised that a husband accused of hiding a gun had been a prisoner of war for two years and couldn't have got hold of a weapon in that time," he said. "As a result, they arrested the wife and her lover and sent them both to Germany."
The stepfather was often a target, according to Mr Joly. "I have seen a case of a boy whose mother divorced and married a Jew. The boy denounced his stepfather because he couldn't take changing his name and because he wanted to spite his mother for her divorce. It often happened in reconstructed families."
The majority of letters were from women, although male letters were higher in proportion to their much smaller wartime population.
According to Mr Joly the issue of denunciation has been almost completely overlooked in history books. This was partly because the French had been loath to delve into the crimes of Vichy, but also because the collaborationist regime did not officially encourage denunciation unlike fascist Germany or Italy
."Nevertheless, it was a fundamental characteristic of Vichy France," he said. "In a sense, it was the only way people could express themselves in a country where there were no demonstrations, no rights, no vote: it was the voice of the people, although often a mean and petty voice or a way of swearing allegiance to the powers that be."
The French language is unique in having two terms for denunciation: "La delation" is its contemptible form while "la dénonciation" is merely doing one's duty and dates back to the French Revolution.
Mr Joly said that the fact that the whole issue can now be studied dispassionately is a sign that France can finally look at its wartime past in an objective way.
"Even ten years ago we couldn't have held this conference. People would have said, 'you cannot rummage around in the past, many of these people are still alive.' Now it is just a subject of scientific study," he said.