Marguerite Jeanne Japy was born on April 16, 1869, in Beaucourt, in the Territoire de Belfort, France. She came from a wealthy industrial family; her father, Édouard Japy, was a prosperous manufacturer, and her mother Émilie Rau came from an equally well-established background. Marguerite married the French academic painter Adolphe Steinheil in July 1890. Through her marriage and charm, she quickly became embedded in elite Parisian society. Her salon was a hub for influential politicians, artists, writers, and aristocrats, drawing names like Émile Zola, Ferdinand de Lesseps, René Lalique, and composer Jules Massenet.

Marguerite was best known for her intimate affairs with powerful men, the most infamous being President Félix Faure of France. They met in 1897 when Faure was working with her husband on an art commission. Their relationship soon turned sexual, with meetings often taking place in the Élysée Palace. On February 16, 1899, Faure summoned Marguerite to the palace, and shortly after her arrival, he suffered a fatal seizure. Rumors—never officially confirmed—claimed he died while receiving oral sex from her, sparking national scandal and long-standing myth.

Following Faure's death, Marguerite maintained relationships with other wealthy and prominent men. She even claimed that a mysterious German visitor once bought back a pearl necklace given to her by Faure and retrieved a secret manuscript he had left with her. Her entanglement in politics and her circle of powerful lovers painted her as both a socialite and an opportunist, but also as someone with secrets men were willing to protect—or kill for.

On May 31, 1908, a grisly double murder rocked Paris. Inside the luxurious Steinheil residence on Impasse Ronsin, Marguerite’s husband, Adolphe Steinheil, and her mother, Émilie Japy, were found dead—both had been suffocated. Marguerite was discovered in her bed, bound and gagged. Her first account to police claimed she had been tied up by four masked intruders dressed in black—three men and one woman—who came searching for documents that belonged to the late President Faure, possibly relating to the controversial Dreyfus Affair. The press devoured this sensational angle, speculating about espionage, secret state affairs, and revenge.

However, investigators quickly became suspicious of her story. With no signs of forced entry, no valuables taken, and Marguerite’s contradictory testimonies piling up, suspicion fell directly on her. The investigation took a strange turn when she attempted to frame her valet, Rémy Couillard, by hiding a pearl she claimed was stolen in his belongings. After that scheme failed, she blamed Alexandre Wolff, the son of her housekeeper, who produced a strong alibi. These false accusations damaged her credibility severely.

In November 1908, Marguerite was arrested and sent to Saint-Lazare Prison. The case, dubbed L'affaire Steinheil, dominated French headlines for months. It revealed not just her tangled web of lovers but also questionable associations and possible motives. Conservative newspapers painted her as a manipulative femme fatale, while anti-government outlets used the affair to stoke political tensions. There were even claims—most unproven—that she had poisoned President Faure, adding yet another layer of mystery to her reputation.

Despite her outrageous lies and attempts to mislead investigators, the jury found no concrete evidence linking her directly to the murders. On November 14, 1909, she was acquitted, though the presiding judge openly referred to her testimony as “a tissue of lies.” The acquittal further polarized public opinion: some saw her as an unjustly targeted woman; others believed she literally got away with murder.

After the trial, Marguerite left France for London and reinvented herself as Mme de Serignac. In 1917, she married British aristocrat Robert Scarlett, 6th Baron Abinger, gaining the title of Baroness Abinger. The marriage ended with his death in 1927, after which she lived quietly in Hove, England. She died in a nursing home on July 17, 1954, and was buried under the name Lena Sheehy. To the end, her story remained one of France’s most sensational true crime mysteries—filled with power, sex, betrayal, and unanswered questions.