The heir to a motoring fortune who will probably be best remembered for his playboy antics, Sachs became Bardot's third spouse when they married in 1966 (she was his second wife).
He had famously courted the French model and actress by flying over her villa on the Riviera in a helicopter and dropping hundreds of roses.
In 1974, Sachs commissioned his friend Warhol to produce this 4ft (1.2m) square acrylic and silkscreen ink on canvas which was based on Richard Avedon's photograph from 1959 (Sachs also owned the original copy of the photo).
Offered with a £3m-4m estimate at Sotheby's evening sale on May 22, the Warhol image of Bardot took £2.65m from a European buyer. Bringing more bidding, the original Richard Avedon photo made £120,000 against a £40,000-60,000 estimate.
The top four prices at the Sachs collection evening sale all came for works by Warhol, the highest being the 1986 Self-Portrait (Fright Wig) which made £4.75m selling to an anonymous buyer. The estimate was also £3m-4m.
Overall, the evening sale made a hammer total of £30.8m with bidding coming from 17 different countries according to Sotheby's. Of the 41 lots offered, 37 (90%) found buyers.
The day sale added a further £4.73m hammer and amongst the 247 lots (228 sold) were some of Gunter Sachs' own photographs including Ascot from 1995 which generated fervent bidding against a £8000-12,000 estimate, selling at £170,000, a new benchmark for a Sachs photo.
The buyer's premium was 25/20/12%