20 Francs

By 1948, the Banque du Congo Belge had been issuing notes through Thomas De La Rue for decades, a relationship that kept production entirely outside the colony itself — a common enough arrangement for Belgian colonial currency, but one that created real vulnerabilities during the Second World War when shipping routes were disrupted. The postwar P#15 series of which this is a part ran across multiple signature varieties (the "F" suffix indicating a specific signing combination), making complete set assembly harder than the denomination's relative availability might suggest.

The watermark is the sole mechanical security feature on this issue — no security thread, no UV-reactive elements.