BERLIN - Three men have been arrested on suspicion of trying to blackmail Germany's richest woman with footage of her steamy encounters with a con man known as the Swiss Gigolo, prosecutors said Friday.

BMW heiress Susanne Klatten "received a letter in mid-June demanding 800,000 euros (1.1 million dollars) and a BMW vehicle, and threatening to sell an intimate video of her encounter with Swiss gigolo Helg Sgarbi to the Italian press if she refused to pay," spokesman Thomas Steinkraus-Koch told AFP.

Upon receiving the letter, Klatten placed an advertisement in a local newspaper saying she was prepared to pay up and giving a contact number.

"They contacted her by phone and we could then identify them ... They were arrested at the 'cash handover'," Steinkraus-Koch said.

The new blackmail operation comes just months after the smooth-talking Sgarbi secretly filmed compromising footage of his affair with Klatten and tried to hoodwink the married mother-of-three out of more than 340 million euros (479 million dollars).

Sgarbi was jailed for six years on March 9 for blackmailing and cheating a string of super-rich lovers, including Klatten.

Klatten is a major shareholder in German luxury carmaker BMW, inherited from her industrialist father Herbert Quandt who saved the Bavarian firm from collapse in 1957 and built it up to a global champion.

According to Forbes magazine's latest list of billionaires, she is the world's 35th richest person, with a net worth of around 10 billion dollars.