Assistant architect for the French section of the 1862 Universal Exhibition in London, and chief architect of the Palace of the Champ de Mars in 1867, with the engineer Jean-Baptiste Krantz (1817-1899), Léopold Amadée Hardy was once again appointed to design the Palace of the Champ de Mars for the 1878 Universal Exhibition. In collaboration with Henri de Dion, an engineer from the prestigious Ecole Centrale, and head of metallic constructions for the Exhibition, he designed a large, rectangular building 300 m wide by 725 m long.
The palace was formed by juxtaposing parallel galleries of metal and glass, richly decorated with brick and glazed earthenware. It was the first major demonstration of polychrome architecture.
The building had vertical and horizontal intersecting walkways giving it the appearance of a draughtboard. The avenues perpendicular to the Seine were divided according to products, whereas those parallel to the river were divided by country. The palace was an extraordinary critical success.
Here, Hardy puts forward a brightly coloured design with red and blue the dominant colours, following the example of the Crystal Palace in the 1851 London Exhibition. Inside, there were large display cases with objets d'art and sculptures in a light space complete with a clear glass roof with a geometric design. The wide avenue, 24 metres high, was punctuated with small columns supporting vases, hung with curtains and lit with chandeliers highlighted with gold. As architectural drawings for the interiors of the exhibition galleries in the 1878 palace were rare, this is important evidence of a construction that has now disappeared.