Here is another portrait of Empress Eugénie by Dubufe from 1854.
Norris and Oswald wrote on p. 114 of Nineteenth-Century Costume and Fashion, "At a public ceremony attended by the Empress in 1855, the skirt of her magnificent cherry-colored velvet dress was entirely covered with Alencon lace valued at Fr25,000." The value (at Fr25 to the dollar and 100-fold inflation - a low estimate) would be 100,000 of today's dollars. This isn't that dress, many of her legendary dresses were never portrayed. Norris and Oswald offer descriptions of Eugénie's gowns by Worth (p.150): Henceforth the Empress of the French, guided by this artist, appeared on various state occasions garbed in white -- in dresses composed of multitudinous flounces of tulle, tarlatan, organdie, crape, gauze, etc. -- excellent foils for her marvelous jewels.
On one occasion it is stated the Empress was arrayed in white satin with one hundred and three flounces on the skirt. At another State function she wore white tulle strewn with diamonds to the value of two millions. White gauze trimmed with silver and soft shades of mauves, pinks, and blues were her particular fancy, and most enchanting with her fair complexion and golden red hair." (Mauve is a synthetic dye that appeared in the late 1850s - gogm.)
Upgrade image posted on 19 October 2012 from the lost gallery's photostream on flickr.