On 2 July 1903 Fournier registered his trademark (No. 16062) at Bern, which covered, “Sheets and envelopes containing facsimile reproductions of old, obsolete Swiss and foreign postage stamps for sale by book dealers, stationers, tobacco merchants and others.” At that time the production and sale of& sold facsimile stamps was legitimate, with awards given at international stamp exhibitions. Fournier considered himself a creator of “art objects” that benefited less affluent collectors. Period magazines and forgery authors referred to his work as "faux de Geneve" (Geneva Forgeries).
In May 1904 he purchased from the Office of Bankruptcy the stock of Louis-Henri Mercier, an earlier producer of facsimiles in Geneva. Mercier had won gold medals for his creations at stamp exhibitions in the 1890s, a claim Fournier later made for himself.
Fournier first did business at 6, Rue Corraterie, soon moving to 11, Rue du Rhone, and by 1906 did a thriving trade at 17, Rue du Rhone. Between Aug 1910 and Aug 1913 he published his own journal, Le Fac-Simile, with 393 pages of text and advertising covering 24 issues. The extent of his creations is captured in his last price list in 1914 with 3,671 different items; many were offerings of the work of Mercier or others. Fournier claimed to have over 20,000 regular customers being mainly dealers.
He also operated a 'philatelic clinic' where stamps could be "repaired" to increase their value.
World War I brought restrictions and censorship to the mails, thus cutting Fournier off from most of his customers. This aggravated his failing health, and he died 12 July 1917. He was returned to his hometown of Croix de Rozon for burial.
An employee of Fournier, Charles Hirschburger, tried to carry on the business without success. He moved in 1922 to Monnetier on the Saleve, where he died on 1 June 1927. His widow sold the lot to l’Union Philatelique de Geneva, consisting of 800+ pounds of facsimiles and all the printing and perforating equipment. The society overprinted the stamps with FAUX (fake) with the reverse printed FAC-SIMILE. They prepared 480 special albums of his work, which were sold in 1928 for the equivalent of $25.00. The society also retained a single 677 page, 5-volume set, of Fournier’s work for their own library. The equipment was donated to the Geneva Museum of History. The balance of the stock was burned on 15 Sept 1928.
The Union Philatelique de Geneve, UPG, notes regarding the purchase of Fournier's stock:
Les faux Fournier
En 1927, l'UPG rachète le fond, le matériel et le stock de l'imprimerie Hirschburger à Genève. Elle acquière ainsi plusieurs caisses contenant le solde des faux imprimés par Fournier, ainsi que les presses à imprimer, à denteler et les stocks qui avaient servis à fabriquer les faux.
Les presses et les stocks d'imprimés ont été remis en 1958 au Musée des PTT à Berne. Les autres pièces des installations de Fournier ont été détruites sous contrôle. 475 albums contenants presque tous les faux marquants ont été vendus à travers le monde pour servir de matériel de référence aux experts. Cette vente a permis de couvrir le prix d'achat du matériel. L'UPG a conservé 6 albums des faux commis par Fournier. Ces timbres ont été exposés à plusieurs reprises. Cette action, unique dans les annales philatéliques, est l'œuvre maîtresse de l'UPG.
