The pavilion designed to house plans, perspectives and relief models of the main ports of commerce, as well as statistical documents relating to the traffic of these ports, was built at the expense of the chambers of commerce concerned: Bayonne, Bordeaux, Boulogne, Caen, Calais, Cette, Cherbourg, Dieppe, Dunkirk, Fécamp, Granville, Honfleur, La Rochelie, Le Havre, Marseille, Nantes and Rouen.
Two decrees of the Minister of Commerce, Industry, Posts and Telegraphs, dated 3 August and 31 October 1899, had fixed the contribution of these establishments at 53,000 francs.
Built on the Quai Debilly, opposite the Rue de Magdebourg, by the architect Lucien Roy, the pavilion consisted of a single exhibition room, preceded by a vestibule which also gave access to a small meeting room for the members of the Chambers of Commerce Committee. The exhibition hall measured 52.60 metres in length and 12.10 metres in width. Overall, the building covered 680 square metres.
As much wall space as possible was needed to display paintings, drawings, graphics and statistical tables. For this reason, the architect decided to light the large room exclusively through the roof.
The building was made entirely of wooden frames covered with staff.
The essential element of its framework was a series of trusses of a common type, normally spaced at about 6m80 apart, resting on masonry blocks and arriving, on the Seine side, at the level of the quay wall. The floor was raised 1.5 metres above the ground.
Between the posts of two consecutive trusses and at mid-distance was an auxiliary post measuring 0.20 x 0.20 m, connected to the previous ones by crossbars and horizontal crosspieces; the truss posts and the intermediate posts were joined in the transverse direction by means of under-floor mouldings. The infill was made up of planks or turntables, which were presented in the field and to which the staff had to be fitted. The joists consisted of 0.65m x 0.17m bastaings laid transversely on three longitudinal headers.
The roofing was made of zinc tiles on non-jointed lathing above the rooms and on jointed lathing for the roof canopies.
Due to the modest budget and the layout of the building, the exterior ornamentation was necessarily limited.
For the facades facing the Seine and the Trocadero Palace, M. Roy had left visible buttresses in the framework, strutting the pavilion in the transverse direction, in line with the trusses. These buttresses were extended beyond the runners by torch-bearing masts, which were linked by a decoration of moulded wooden frames with the names of the ports. The roof canopy rested on brackets, below which was a frieze of staff frames also dedicated to the names of the seaports. Towards the Seine, a balcony projecting one metre and 13.5 metres in length stood out in the middle of the facade and was accentuated at the top of the ridge by crest motifs; the opposite facade had a similar balcony, on which the fire station had been installed.
The entrance facade (front gable) was completely decorated in staff. A large staircase led to a very large bay, divided into three parts by a frame decoration. A turret and a semaphore stood on the corner room adjoining the vestibule and reserved for the committee meetings. The downstream gable was extremely simple and had a secondary entrance.
Inside the large room, a decorated velum, stretched over the entire ceiling surface, filtered the light received from the skylight and hid the roof structure. Beneath this velum, at the top of the walls, ran a painted frieze, composed by M. Onillon.
Two tones had been adopted for the colouring of the façades: very light violet on the staffs; blue on the exposed wood. Inside, the walls were painted with red-brown glue.
©Rapport général administratif et technique 1900