20 Francs

The Banque de l'Algérie was a private institution operating under French colonial charter, not a state central bank — its notes circulated as legal tender in Algeria from 1851, but the metropolitan Banque de France had no direct authority over its issuance. This 20 Francs type had an extraordinarily long print run, used across three and a half decades and two world wars, which means dating individual examples requires close attention to signature combinations rather than the printed date field.

Bellenger and Pannemaker were both associated with the Parisian intaglio trade. Pannemaker came from a distinguished dynasty of engravers active since the mid-nineteenth century — the family name appears across French colonial and metropolitan note production well into the early twentieth century.