The rare camera fetched €1.32 million (£1.15m) at the Westlicht sale - four times the amount it raised at the same Vienna auction house less than four years ago.
Described as in 'excellent and fully working condition', the seventh in Leica's O-Series line-up was made in 1923 to test the market for 35mm stills cameras. It preceded the launch of the mass-produced 35mm Leica camera, the Leica 1, in 1925.