An update: Reader Arndt has helped me figure this out.
When I saw this pan for sale online I leaped at it because it matches my two “Louise” sauté pans with their unusual and distinctive bar-shaped handle baseplate and flush-set rivets. To my eye these pans are an intriguing combination of 19th-century construction and an almost modernist mid-20th-century styling. I would love to know more about who made them and when.
This third saucepan adds an additional clue: a small stamp reading “F. EKHART IN WIEN” below the handle baseplate. I haven’t been able to identify an F. Ekhart in Vienna that could have made or sold copper cookware. I’m limited to Internet research and while I can usually muddle through with French sources I do not speak or read German and it hampers my ability to navigate online resources.
A reader in Germany named Arndt has very helpfully found some other examples of this style of pan with a maker’s mark on it. Behold the work of A. Fauser & Sohn of Vienna.
Internet records are a little slim, but I know they were active around 1899. The list of official suppliers to the royal court of Austria in 1899 includes “Otto Fauser, Coppersmith; Brand: A. Fauser & Son.” I’m starting the process of researching this company to find its years of operation, but this is a very helpful start. This likely means that F. Ekhart was a business of some kind, perhaps a store or restaurant.
Arndt, I cannot thank you enough. You have been a huge help!