Numerous artists were commissioned to work on the mosaics and glass floors that form a constant theme running right through the building.                                                                     
In the Grand Palais, the floor mosaics generally made of small pieces of marble, granite and other materials in opus incertum (assemblies of small blocks of irregular stone on mortar put together to avoid any gaps). The glass floors are tablets made to measure in moulds with motifs that take the form of the drawing as designed by the artist. They form very strong floors and were very much in fashion at the Belle Époque (1890-1914) because of they way they illuminated the rooms below.