The 13 x 10 1/8 inch (32.5 x 22.5 cm) gelatine silver black and white photograph was taken in 1993, when Bruni was one of the world's top fashion models, and is being sold by art collector Gert Elfering.

It is expected to fetch $3,000 (1,500 pounds) to $4,000 when it is sold in New York on April 10, according to the Christie's web site.

Sarkozy married Bruni, 40, in February after a whirlwind romance that began shortly after his divorce from his second wife Cecilia.

Their relationship has coincided with a sharp fall in Sarkozy's approval ratings which have tumbled as voters judged that the president's glitzy lifestyle jarred with his responsibilities and status as head of state.

Sarkozy and his new wife are due to pay a state visit to Britain this week during which they will be hosted by Queen Elizabeth at Windsor Castle.

(Reporting by James Mackenzie, edited by Richard Meares)