1 Franc Monaco essai bleu

Monaco's 1920 small-denomination notes were a direct response to the wartime and postwar coin shortage that plagued France and its neighboring territories — the Principality issued its own fractional paper rather than rely on an increasingly unreliable supply of French centimes. The "essai bleu" designation marks this as a color trial, printed in blue rather than the issued colorway, and such proofs from Veuve A. Chêne rarely escaped the printer's premises in any quantity.

Albert Berthe's engraving work for Monaco during this period is relatively obscure compared to his broader output. The JP#136 reference covers at least three catalogue variants (06, 07, 08), suggesting multiple proof states were documented — unusual granularity for a note of this denomination and this printer.