This is a 3 flight monumental elliptic stair with a 2 meter outside radius for the renovation of a federal building.
Of special note, the stringers are 57mm (2 1/4′) thick steel plate with a groove on top to receive a curved glass railing. They also have an internal radius of only 580mm (23″) with a slope of 48 degrees and the glass railing will be tempered rather than laminated.
The total weight is 25 imperial tons and the finishing conforms to CISC AESS level 4.
Photos show only 2 flights with temporary supports.