published in The Economic Journal (vol. 100, no. 399, March 1990) disputed Thomas Sargent's popular explanation to the sudden end of hyperinflation as result of a wide-ranging fiscal "regime change". The role of dollarization and of currency reforms were wrongly downplayed by Sargent, as argued by Franco. "The Rentenmark Miracle" published by Rivista di Storia Economica (Second Series, Volume 4, 1987), then republished in Barry Eichengreen (ed.) Monetary Regime Transformations London, Edward Elgar Publishing Ltd, 1991, was an account of the unique experience in Germany of Wertbestandiges Notgeld - that is, emergency monies of private issuance and with "stable value" as they had indexation clauses -, and the way this led to the rentenmark experience. As argued by Franco the rentenmark was a crucial step in the German stabilization, and not a "cosmetic measure", as put by Thomas Sargent. In fact, the rentenmark model was very relevant for the design of the Brazilian 1994 monetary reform, known as "Real Plan", in which a similar quasi-currency, under the name o URV (acronym for Unidade Real de Valor) played a vital role for the ending of Brazilian hyperinflation. Much later, in 1995, Thomas Sargent wrote an article on the Brazilian URV, evoking the German experience with the rentenmark and arguing, as per the mathematician David Hilbert, that one could not solve the hyperinflation problem by "changing the name of the independent variable". The URV, argued Sargent, would have been "a sideshow that hasn't touched the fundamental causes of inflation", and again Franco took issue with that, writing in 2017, but this time on the back of the successful adoption of the URV mechanism. According to Franco: "Understandably", Brazilians "did not take these observations seriously" as "the country was enchanted by the URV mechanism in view of practical problems it solved elegantly, efficiently and voluntarily, so that they received with blunt indifference a thesis from an outside observer claiming that the mechanism had no utility". Economic history In sequence to the work on monetary reforms in the early years of the Republic, Franco published several pieces on the Brazilian monetary experience in the years prior to the Great Depression. All this work is in Portuguese except "Aspects of the Brazilian Experience with the Gold Standard", in Pablo Matín Aceña and Jaime Reis (orgs.) Monetary standards in the periphery: paper, silver and gold, 1854-1933 (London, Macmillan Press. 2000). Later, his research on the early