On 16 July 1947, banknotes were issued for Saar denominated in marks, which replaced the German Reichsmark. But in November 1947, the French government reintroduced the French franc as the official currency. Between 20 November 1947 and 15 January 1948, all notes and coins had to be exchanged, the exchange course being 20 Saar marks = 1 franc. It was not before 1954 when the government of the Protectorate issued new coins denominated in 10, 20, 50 and 100 francs. But the coins resembled the coins of the French franc and were officially and legally not a currency of their own, but only local issues of the French franc.
After a referendum about the future status of the region, Saarland was incorporated into the Federal Republic of Germany as a Bundesland on 1 January 1957. The economic integration into Germany was completed with the withdrawal of all Saar-Franken two years later. On 29 June 1959 the federal ordinance "Verordnung zur Einführung der Deutschen Mark im Saarland" stipulated that - with effect from 6 July (§ 1) - all debts, credits, deposits, wages, rents, fees, interest servicing, or amortisation payments, and other obligations, as well as cash reserves and prices denominated in francs were to be converted at the rate of 100 francs = 0.8507 Deutsche Mark (§ 2). The conversion had been brought forward by half a year because of the accelerating depreciation of the French franc. The date was kept secret (called "day X") to avoid currency speculation, and only published two days in advance. The freedom to fix new prices was maintained, but especially temporarily or permanently fixed obligations, not to be altered at any time, were not to be renegotiated but converted at the rate fixed.