He worked in the workshops of the Rhenish Railway Company (Rheinische Eisenbahn-Gesellschaft) in Cologne, and then in the blast furnace and steelworks of Hörder Vereins.

In the mid-1880s Fremery and the Austrian engineer Johann Urban (1863–1940), whom he had met in Amsterdam, took over the technical management of a light bulb factory in Gelnhausen.

[1] The Swiss chemist Matthias Eduard Schweizer (1818–60) had found in 1857 that cotton could be dissolved in a solution of copper salts and ammonia and then regenerated.

[2] In 1890 the French chemist Louis Henri Despeissis invented the cuprammonium process for spinning fibers from cotton dissolved in Schweizer's reagent.

[3] After two years Rheinische Glühlampenfabrik production had reached acceptable volumes, and from 1894 the company was delivering lamps to France in significant quantities.

[8] The success of the cellulose fiber developed by Hilaire de Chardonnet encouraged Fremery and Urban to investigate making artificial silk, which they named "Silkimit".

[3] In Oberbruch in 1898 they established the first factory in Germany to economically produce artificial fiber, using a patent for manufacture of rayon made from cellulose in a copper-ammonia solution.

In 1911 VGF bought the Henckel von Donnersmarckschen Kunstseide- und Acetatwerke rayon factor in Stettin, and acquired the patent rights for viscose manufacture.

[1] The company headed by Count Guido Henckel von Donnersmarck (1830–1916) had been the first in Germany to use the viscose process invented by Courtaulds in Britain.