500 Francs / Frank = 100 Belgas / Belga

The "Belga" was a trade unit introduced in 1926, pegged at five francs, designed specifically to simplify foreign exchange calculations during the interwar period. By the time this note was being issued, the dual denomination labeling had become something of an anachronism — the Belga was never popular in domestic use and would be formally abandoned in 1946.

The date range spans the German occupation, which matters. From May 1940 onward, the Banque Nationale continued operating under Reichskommissariat supervision, and notes of this type circulated alongside German-issued Reichskreditkassenscheine. The occupation authorities did not suppress Belgian note issue — they exploited it.