A French magazine has lost its appeal against fines imposed after it published photographs of the Duchess of Cambridge sunbathing topless.

Two senior editors at the celebrity magazine Closer, and two photographers suspected of taking the long lens shots in 2012, had appealed against the fines, which were issued in September 2017 for breaching the privacy of the duchess.

A French appeals court on Wednesday upheld the two €45,000 fines – the maximum allowed – and dismissed the appeals.

The magazine had published grainy photographs of the duchess wearing only bikini bottoms while she and her husband were on holiday at a private chateau owned by Viscount Linley, the Queen’s nephew, in the Luberon region of south-east France.

Six people went on trial after the pictures were published in Closer, and a local newspaper, La Provence. They were splashed across the cover of Closer under the headline: “Oh my God: the photos that will go around the world.” More topless photographs of the duchess featured inside.

In a letter read out to the court in May last year, William said the case had brought back painful memories of the paparazzi who regularly hounded his mother, Diana, Princess of Wales, who was killed in a car crash in Paris in 1997 while being pursued by photographers.

The magazine’s editor, Laurence Pieau, and its publisher, Ernesto Mauri, were fined €45,000 last year while the photographers were ordered to pay €5,000, with another €5,000 payable if they reoffended.

The magazine was also ordered to pay €100,000 in damages to the royal couple, considerably lower than the €1.5m the couple’s legal team had demanded.

The court of appeal in Versailles, west of Paris, also upheld the fines handed to the two photographers suspected of taking the pictures, who deny responsibility.

The French prosecutor Marc Brisset-Foucault had told the court: “There was an absolutely unacceptable breach, not only of the privacy and the private lives of these two individuals, but also of the dignity of a woman.”

Paul-Albert Iweins, a lawyer acting for Closer, had asked the court to either cancel or reduce the fines imposed by a lower court in the Parisian suburb of Nanterre, arguing that they were excessive for a privacy case.