1 Franc Red and blue

Constantine's Chamber of Commerce resorted to issuing its own emergency fractional notes in 1920 because the postwar coin shortage in French Algeria had become genuinely disruptive to retail commerce — small denominations had effectively vanished from circulation. Chambers of Commerce across Algeria and metropolitan France were authorized to fill the gap, producing a patchwork of locally issued scrip that varied widely in quality and staying power.

Jules Carbonel was the dominant commercial printer in Algiers during this period, handling a significant share of the Algerian chamber notes. The two-color printing — red and blue — was a deliberate anti-counterfeiting measure on a note that would otherwise have been trivially simple to reproduce.