The building on the Champ de Mars is 2132 feet by 1148. A wide and lofty vestibule runs across the full extent of each end, and these afford the most imposing interior views of the building. They are known respectively as the Galérie d'Iéna and Galérie de l'École Militaire, from their vicinity to the bridge and school respectively. Being lofty themselves, and having central and flanking domed towers which break the uniformity, their fronts form the principal façades of the building, of which, architecturally speaking, they are the principal entrances; but in fact, as happens with buildings of such acreage, the actual inlets depend upon the predominance in numbers of the people on one or another side of the building, the means of approach by land and water, and the contiguous streets of favorite and convenient travel. In the present case the bulk of the people reach the grounds either by water at the south-east corner or by land at the intersection of Avenue Rapp with the Avenue Bourdonnaye, which latter bounds the Champ de Mars on its southern side.
The end-vestibules are connected by five longitudinal galleries on each side of the open area in the middle of the building. The five galleries on the southern side belong to France, and the five on the northern side are divided by transverse partitions among the foreign nations present, in very greatly differing quantities. England, for instance, occupies nearly two-sevenths of the whole space devoted to foreign exhibitors, being more than the sum of the amounts allotted to Spain, China, Japan, Italy, Sweden, Norway and the United States. The end-vestibules have curved roofs with highly ornamented ceilings of a succession of flat domes along the centres, with three rows of deep soffits on each side, gayly painted. The walls are nearly all glass in iron frames, and the panes of white glass alternate in checkerwork with those having blue tracery upon them. The whole building is principally of iron and glass, the roof of wood, with zinc plates and numerous skylights over the interior galleries. The machinery galleries of each side are much the largest of the longitudinal ones, and have high roofs with side windows above the levels of the roofs on each side of them; but the four other galleries on each side of the building have quite low ceilings, which make one fear for the quality of the ventilation when the heat is at its greatest.