According to Dorotheum, they "were originally made by Joh. P. Winkler, purveyor to the imperial and royal court, and retained by him as a memento. Ordered in 1889, the tights were never delivered following the Empress' assassination."
I think the website may have made a typo with the date as the Empress was assassinated in 1898.
The tights had an estimate of €2,400- €3,400 and sold for €3,500.
(Photocredit: Dorotheum Vienna)