Specialists in monumental rosettes will not be mistaken: it is a trompe l'oeil. I do not know of any rosette to date whose structure would be made of riveted steel, but the effect seems normal and integrates perfectly with the other materials in this Protestant temple. Despite a design dating back to the Eiffel period, this stone rosette on the exterior façade had been smoothed with plaster on the inside, resulting in large, poorly proportioned painted bands around these beautiful stained glass windows. The imitation of superimposition of riveted steel angles furnishes these spaces and makes them more balanced.
58 rue de Lille, Paris 7ème
58 rue de Lille, Paris 7ème