It rises the main hall, which marks a new approach of the layout space in department stores. By its monumentality, this space becomes the center of the store. The dome is 43 metres high, surpassing from 14 metres the facade.
At a time when the use of reinforced concrete is still at its beginning, the metal dome rests on a concrete structure of 10 circular poles. Using innovative techniques, this project, conducted in a relatively short time, is also an impressive scale. Therefore, an intermediate floor will be set up in the upper part to build a scaffolding tower that will serve as support to meet the firm and metal that will form the arches of the dome. These proposed structures are based on a metal ring, Eiffel structure, and end at the clef by a lantern, also metallic. It is interesting to note that the canopy is double-enveloped: the ornate interior conceals the structure of the outer shell, while the air gap between the two walls is an ingenious thermal protective buffer against temperature changes ( to see the 4th and 5th floor of the store).
From the perspective of ornamentation, the coupole often referred as the dome néobyzantine, mainly reflects the influence of Orientalism on the decorative arts of this period. From inside this time, the ironwork beams richly carved with floral and attributed to Edward Schenck, rest on the concrete to cercle the ten panels of stained glass of the dome. These windows of blue colors but mostly orangey diffuse warm light, related to Theophile Bader and his conception of the department store as a “luxury bazaar”. They are the work of master glassmaker ,Jacques Gruber, a major artist of the School of Nancy and Art Nouveau movement.
Between each metal arc of the coupole, a coat of arms (10 shields in total) symbolizes a city where Galeries Lafayette was implanted in 1912 (purchasing offices or counters): Lyon (silk), St Etienne (ribbon) … etc. It is a real textile geography of France.