The late German-born Chanel designer Karl Lagerfeld was famously precise, exacting and known to hold a grudge, but his final wishes concerning the beneficiaries of his vast fortune could now be overturned beyond the grave in a looming court battle.

Seven years after Lagerfeld’s death from cancer, an unnamed plaintiff has come forward to challenge the haute couture titan’s last will and testament.

The estate’s executor, Christian Boisson, has contacted Lagerfeld’s surviving nieces and nephews to inform them that they could now inherit his millions if the case is successful, German media reported. Care of his beloved cat, provided for before his death, would not be affected.

Lagerfeld, one of the most influential figures in global high fashion across decades, but an enigmatic figure behind dark glasses, had no spouse, children or surviving siblings when he died in 2019 aged 85.

His will dated 29 April 2016 shut out his deceased siblings’ children, leaving his accumulated wealth and property, valued at about €200m, to a tight cadre of confidants.

They are believed to include his assistant and bodyguard Sébastien Jondeau, teenage godson Hudson Kroenig and models Brad Kroenig and Baptiste Giabiconi. Giabiconi has described himself as “at the top” of Lagerfeld’s inheritors and said the designer once made an abortive attempt to adopt him as a son.

The German magazine Bunte reported that the descendants of Lagerfeld’s late sisters, Christiane Johnson, who died in 2015, and Thea von der Schulenburg, who married into the aristocratic Schulenburg clan and died in 1997, had received letters from the executor.

“The interpretation of the will is being contested,” Boisson wrote, according to Bunte. “At present, the rights of the heirs are therefore uncertain.”

Lagerfeld lived in Paris and died on its outskirts but maintained what he called his primary residence in Monaco, meaning that French and Monegasque law, which generally designate the next of kin as rightful heirs, would apply.

The plaintiff, however, would have to make the case that Lagerfeld, born in Hamburg in 1933, was not of sound mind when he signed the will.

German media were quick to note that Lagerfeld’s 14-year-old fluffy pet cat Choupette, acquired from Giabiconi, can regardless continue to rest easy in her life of luxury.

While he was still alive, the designer bequeathed a home and garden in France as well as a brimming bank account to his housekeeper Françoise Caçote for her to care for the beloved sapphire-eyed white Birman after his death.

Because the gift was made long before his passing, it is seen as beyond the reach of any legal challenge to his will.

Choupette’s gilded lifestyle is the stuff of legend – eating out of porcelain dishes, sleeping on Chanel fabrics and reclining in Louis Vuitton monogrammed cat carriers.

She has her own verified Instagram account with 278,000 followers and has earned an income as an advertising mascot for companies such as German luxury car giant Audi. When Lagerfeld died, speculation ran rampant that she was listed as a beneficiary in his will.

Beyond his fortune from couture, Lagerfeld kept a number of luxury properties, including his vast Parisian flat and sumptuous Biarritz villa, and owned a sizeable stock portfolio as well as collections of art and rare books.

Little is known about how and when Lagerfeld fell out with his blood relatives, but they were understood to be estranged in the last decades of his life. A 2023 BBC Two documentary said he had not seen one of his nieces in five decades.

However, another niece, an American, said that while she hardly knew him, Lagerfeld was “generous”, even designing her wedding dress at no charge then flying the garment over on Concorde to be there in time for the ceremony. She told the film-makers she expected nothing further from her late uncle: “There is no need.”

Lagerfeld worked up to his death on several collections a year for Chanel, for Fendi and for his own label, Karl Lagerfeld. He said while still alive that he had frequently tinkered with his will: “Even one funny look from someone and they’re out.”

It is not the first time Lagerfeld’s named beneficiaries have had to worry their inheritance would be snatched away.

French finance authorities have reportedly demanded up to €40m from his estate in back taxes, Germany’s Bild newspaper said, on the grounds that his actual primary residence was not in Monaco, a common tax haven.

Boisson could not immediately be reached but his associate Frédéric Heurté told Bild: “We are bound by confidentiality. Therefore, I am not permitted to comment on anything concerning Karl Lagerfeld’s estate.”

Approached by Bild, Thea’s daughter Thoma von der Schulenburg also declined to comment.