Marie Arbant, 43, was rescued from prostitution in 1987 by an investigating judge who then fell in love with her.
He was later dismissed for dishonouring his profession. Early this week Marie tried to rescue the judge.
She killed herself, apparently in the belief that her death would enable him to resume his ruined career.
Marie's body was discovered on Tuesday by Philippe Le Friant, the former judge, who was no longer her lover but was still her closest friend.
Mr Le Friant was hounded out of the legal profession in 1988 for breaking a few procedural rules to help Marie, who had been "sold" into prostitution by her husband when in her twenties.
Mainly, the judge insisted, he was persecuted out of professional snobbery, even though he and Marie did not become lovers until after he was dismissed.
The couple had written a book together, The Judge and the Prostitute.
They had twice gone on hunger strike to press his claim for reinstatement. They had been the subject of dozens of articles and television programmes in France.
The possibility of a film about their story was under discussion.
After being given, and then losing, a job as a legal lecturer, Mr Le Friant had found work in a factory, until a machine crushed his hand. He was living on a disability pension of pounds 60 a week.
A few weeks ago Marie wrote to the Justice Minister, Elisabeth Guigou, threatening to commit suicide unless Mr Le Friant, 51, was given another job in the judicial system. "Do I have to disappear before Philippe can go back to his work?" she asked.
On Tuesday, Mr Le Friant, after hearing nothing from Marie for a week, found her body in her small apartment in the industrial town of St Etienne. She had taken an overdose of barbiturates. She left no note.
The couple met in 1986, when Mr Le Friant was an investigative judge in Lyons, known as the "whores' judge", because he specialised in dismantling prostitution rings. A man of left-wing sympathies, he also belonged to a voluntary organisation that tried to persuade street-walkers to abandon and give evidence against their pimps. (Prostitution is legal in France but pimping is not).
"It was long and delicate work," he wrote later. "The girls would often crack under the strain ... Marie stood out as different from the others, because there was no ambiguity about her attitude to the pimps: she hated them."
One night in 1987, he got a desperate phone call from Marie, saying that her life was in danger because she had given information to him. He invited her to hide at his home and informed his boss of what he had done.
Disciplinary procedures were started against him. The following year he was dismissed for having "betrayed the honour of the magistracy". Specifically, he was accused of having given Marie a weapon to protect herself and having interfered in legal proceedings to help her, including one case concerning the custody of her two daughters.
Mr Le Friant began a long campaign for his reinstatement, which appeared to have succeeded when he was granted a pardon by the late President, Francois Mitterrand, in 1993.
No suitable post was offered to him by the judicial establishment, however.
It seemed that he was about to be employed when the government changed in 1997 and the new Justice Minister, Ms Guigou, put his case on hold.
After his dismissal, Philippe and Marie became lovers, living together from 1988 to 1995. Even after they split, they remained friends and Marie went on hunger strike with him to dramatise his grievances last year and again in January. She appeared increasingly depressed, however, and convinced that she was to blame for all that had happened.Reuse content