Sale of the 20th century: a playboy's Pop Art

International playboy Gunter Sachs was friends with Andy Warhol and married Brigitte Bardot after showering her with roses from a helicopter. After his suicide last year, it has emerged that his art collection will be auctioned in London this spring. Sotheby's yesterday announced it was to put almost 300 works up for sale, saying it was the "most remarkable and prestigious single-owner collection to appear at auction".

The German-born millionaire dubbed one of the last "international men of mystery" shot himself last May at the age of 78. He left a note explaining he had "no hope illness A" believed to have been Alzheimer's disease.

The lots cover artworks from his 50 years of collecting, with a series of pieces by Warhol as well as Roy Lichtenstein and Salvador Dalí that are expected to fetch a total of more than £20m.

Sachs was also an accomplished photographer and documentary film-maker himself as well as a European bobsleigh champion. He eschewed the title of playboy saying: "I would rather call myself a gentleman" but once boasted of "never having worked a day in my life".

He became a popular figure on the Riviera, was often seen in the company of beautiful women, including Britt Ekland, Tina Onassis and Soraya Esfandiary, the former Queen consort of the Shah of Iran.

Cheyenne Westphal, chairman of contemporary art for Sotheby's Europe, said the collection "truly captures the essence of Gunter Sach's life in the 1960s and 1970s and reveals his little-known side as one of the most visionary and influential collectors of the 20th century."

Sachs started collecting in 1959 after moving to Paris, where he became friends with artists including Yves Klein and Dalí. Alongside these, works by Max Ernst, René Magritte and Yves Tanguy will be up for auction in May.

The heir to the Opel car dynasty met Warhol in St Tropez in the 1960s and would later and put on his first large exhibition in Europe in his Hamburg gallery. Not a single picture sold on the opening night, with Sachs secretly buying half to save his friend from embarrassment. It proved a great investment.

Warhol's portrait of Brigitte Bardot, based on a photograph taken by Richard Avedon, is included in the sale. In 1966, Sachs had hundreds of roses dropped from a helicopter into Bardot's garden after spotting her in a bar. She said later: "I thought he was magnificent. I was hypnotised." Sachs said: "It was love at first sight and when we spoke it was as though lightning had struck."

The French art critic Pierre Restany described Sachs in 1967 as "a true art lover... one of those last few people of taste, on the verge of becoming extinct".