The London Times, London, U.K., from Adam Sage in Paris, May 3, 2005

A FRENCHMAN has won a ground-breaking ruling against his former wife and her lover, ordering them to pay back the money that he had spent on bringing up a child he had mistakenly assumed to be his own.

The man, named as G in the ruling, was awarded €23,000 (£15,600) after a DNA test revealed that he was not the father of the 13-year-old child, Astrid.

He had raised her as his own daughter, paying for her food, clothing, toys, schoolbooks and holidays, the Caen Appeal Court in Normandy said. It added that his former wife, B, from Cherbourg, had always had doubts about the identity of Astrid's father: she was unsure whether it was her husband or her lover.

The judges said that she had committed a "fault" by failing to tell her husband that she had been having an affair at the time of the conception and that she did not know whose daughter Astrid was.

The court denounced the lover, named as L, who suspected that Astrid might have been his child, but who also failed to air his suspicions.

In the ruling, the wife and the lover were ordered to pay the former husband €15,000 in compensation for the money that he had spent on Astrid. "It has not been proved that he would have voluntarily carried out his natural duties (towards Astrid) knowing that he was not the father," the judges said. They were required to pay a further €8,000 to cover the "moral and psychological damage suffered by G, who finds himself deprived of his fatherhood of Astrid," the court ordered.

Maître Gérard Méjean, a French family law specialist, said: "In this type of case, mothers who cheat are condemned to pay. They can no longer make and unmake fathers with impunity."

Pierre Murat, Professor of Law at Grenoble University, said: "The court has taken account of the good faith of the father, who believed the daughter to be his own. The difficulty is evaluating exactly how much a man has spent on a child. That's very complicated."

The case arose when B left her husband, sought a divorce and married L — with whom she had been having an affair throughout her first marriage. She decided to settle the issue of Astrid's paternity once and for all and asked a laboratory in London to carry out a genetic test. In France such tests only can be ordered by a court. When scientists said that they were 99.85 per cent certain that L was the father, a French judge gave him parental authority and changed Astrid's surname.

The girl, who had been living with the man she had thought to be her father, G, was told to move in with her mother and her real father.

In their decision the Caen judges said: "The situation with which she is confronted is particularly disturbing," adding that she was subjected to "psychological pressure". The court granted G's request to continue to see Astrid.

About 3,000 French people go to court every year to demand DNA tests to settle such disputes. Many hundreds more ask for private tests to be undertaken abroad, most notably in Britain, Belgium and Germany.

The demands for DNA tests often involve men setting up home with a woman who already has a child. Many say that the child is theirs to simplify administrative procedures with France's bureaucracy. Should a couple separate, the man may deny paternity to avoid paying an allowance and ask for evidence to prove his argument.

In one recent case a man was held liable in a civil action after his teenage "son" raped a woman. He was ordered to pay her damages. But he told the court that the boy was not his, and produced a DNA sample to prove it. He won his case.