It must rank as one of the most exclusive, even secretive, films made in Germany.

Only a few hundred executives will watch, this month, a specially commissioned biopic of Reinhard Mohn, the controversial founding father of the Bertelsmann publishing group.

Bertelsmann is one of the five biggest media companies in the world, yet there seems to be no intention to put the film on general release. It is a personal, and pricey, present from the board to Mr Mohn to celebrate his 85th birthday.

The company is shy of saying how much the film cost but it must have run into the millions. The star role is played by Sebastian Koch — who played Hitler’s favourite architect, Albert Speer, in the TV drama The Devil’s Architect — and is being produced by teamWorx, which made Dresden, Germany’s most expensive made-for-television film. The most delicate aspect of the film is not so much the corporate extravagance as what it has left out of the biography of Mr Mohn. For fear of offending Liz Mohn, 65, his powerful current wife, no mention is being made in the film of the first Mrs Mohn.

This is a pity since Mr Mohn’s first marriage provided an extraordinary insight into the man who converted Bertelsmann from a modest family-run enterprise printing prayer books into one of Germany’s few multinational media giants.

It owns Random House, Knopf and Doubleday, thus dominating the US publishing market. Its magazine outlet, Gruner and Jahr, is a European market leader with more than 120 titles. The group owns RTL, the largest European private television broadcaster, and the BMG music group, which has the likes of Justin Timberlake and Britney Spears on its books.

For years Mr Mohn ran parallel families, fathering three children with his wife Magdalene and three with his mistress Liz, a company telephonist. Liz was encouraged to marry a Bertelsmann book editor to camouflage the relationship.

When Mr Mohn visited his lover, her husband would be sent to the cellar to spend the night. The marriage formally broke up in 1977. Magdalene came back from a spa weekend to find a letter on the kitchen table that said: “Our marriage was a mistake.”Mr Mohn’s wartime past is also expected to be given short shrift. His father, Heinrich, was a financial contributor to the SS and Reinhard was in the Hitler Youth.

About 700 executives have been invited to the showing in a Berlin cinema on January 22. There are no plans to show the film on RTL. First press reactions — in papers that are not part of Bertelsmann — have been mocking. “Rich merchants and vain rulers have let themselves be portrayed by painters for centuries,” Die Welt said yesterday. “In that sense Nico Hofmann [of teamWorx] should be seen as the Frans Hals of the 21st century.”

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