FRANKFURT (Reuters) - Germany’s wealthiest woman, and one of its most discreet, has gone public with a tale of how a lover filmed their hotel trysts and demanded millions of euros not to reveal them.

Munich state prosecutors confirmed on Tuesday that they were pursuing a case against a man accused of blackmail by Susanne Klatten, a member of the Quandt family, famous in Germany not only as the leading shareholders in car-maker BMW but also for their low public profile.

The mass-circulation daily Bild said Klatten, a 46-year-old married mother-of-three, had first met the 43-year-old Swiss at a hotel bar. It said he had described himself as a multilingual special envoy for war zones, although in reality he sold chicken at a fast food stand.

Later meetings, including hotel-room rendezvous, were secretly filmed by an accomplice and used in an attempt to extort 40 million euros ($51 million), the paper said.

A spokesman for Klatten said the pictures had been taken in late 2007.

“Afterwards, the blackmailer asked for an advance of several million euros and later tried to get a far higher amount. In January 2008, Mrs. Klatten lodged a legal complaint with the state prosecutors in Munich,” he said.

Neither the alleged blackmailer nor his lawyer could be reached for comment. Newspapers reported that he had defended his actions, saying he wanted to avenge his Jewish grandfather’s forced labor in Klatten’s family’s factories during the war.

The Quandt dynasty had close ties to the Nazi party and built its fortune supplying German army and railway worker uniforms. Klatten’s grandfather’s first wife went on to marry Nazi propaganda chief Joseph Goebbels.

The family recently pledged a full investigation after a television program revealed that forced labor had been used in their factories as part of the Nazi war effort.

Klatten’s wealth is estimated by Forbes magazine at almost $10 billion, making her the 68th richest person in the world.

She owns just over half of the chemical company Altana as well as a 12.5 percent holding in BMW.