The most beautiful cars in the world?

A convertible (open-top) Mercedes-Benz car made in Germany more than 80 years ago – with a colourful and intriguing provenance - is expected to sell for up to €7 million at auction next month.

International auctioneers Bonhams said its sale of classic and vintage cars in Paris on September 3rd would feature a Mercedes-Benz 500K Special Roadster that was unveiled at the Berlin Motor Show in 1935. Only 29 models of what is, arguably, the world's most beautiful car were made and this one has survived against the odds. Bonhams said the superb car which represented "the pinnacle of 1930s automotive technology" was being sold by "the oldest industrialist family in Germany".

It was originally bought by Hans Friedrech Prym (1875-1965) of the Prym dynasty, a family who for 12 generations had produced haberdashery, copper and brass products.

Philip Kantor, Bonhams' European head of motoring said, "It's no surprise that the 500K appealed to Hans Prym, who was a highly successful industrialist", as the car was "vast, stately, and incredibly powerful, only to be possessed by the elite", He said it is in magnificent condition and is expected to attract strong bidding.

In 1945, at the end of the second World War, the car was stolen from Hans Prym’s estate, after which it disappeared without trace. It was later discovered in America – but how and why it was shipped across the Atlantic remains a mystery – and passed through the hands of several collectors. It turned up in an auction of classic cars in California in 2011 and was bought by a Dutch collector for $3,7 million and shipped back to Europe. However, when the new owner took the car to Essen in Germany to display it in an exhibition of classic cars it was seized by the authorities. The Prym family claimed that the car had been stolen – and not sold – by their grandfather in 1945 and the car was returned to them. Mr Kantor said: “Now this incredible motor car is safely back in the hands of its rightful owners, who have elected Bonhams to offer it at auction.”

The auction takes place on Saturday, September 3rd, at the Château de Chantilly on the northern outskirts of Paris. The Bonhams Chantilly Sale also includes four classic cars also from 1930s Germany made by Horch, a company founded in 1904 that is one of the ancestors of the present Audi company.

Bonhams said: “In its short lifetime, the company produced several magnificent motorcars”, and it will offer for auction a 1937 Horch 853 Stromlinien Coupé (€600,000-€900,000); a 1937 Horch 853 Spezial Roadster Continuation (€1 million-€1.3 million); a 1938 Horch 853 A Sport Cabriolet, (€700,000-€900,000); and a 1934 Horch 780 B Cabriolet (€600,000-€900,000).