In that period when other African currencies have collapsed or are worth a fraction of their value even a decade ago, 14 Francophone African countries have relied upon a stable, convertible currency linked to and backed by the French treasury. The Communaute Financiere Africaine (CFA) Franc was worth 50 to the French franc when it was launched in 1948 and it has remained unchanged until today's devaluation by 50 per cent, to 100 to the franc.
The decision to devalue was taken by officials from the member countries who met representatives of the International Monetary Fund in the Senegalese capital, Dakar. The devaluation will hit poor countries hard. It represents a shift in French Africa policy away from its former colonies and towards a more pragmatic, commercial approach. It may mean a weakening of the relationship between Europe and Africa.
French support for the CFA, the currency of some of the world's poorest countries, such as Mali and Niger, has been a practical manifestation of the remarkably durable links between France and its former African colonies. Even now France spends on sub-Saharan Africa nearly 10 times as much as Britain in aid. At dollars 3bn ( pounds 2bn) in 1990 - the most recent figure - this is in addition to the uncounted burden of the CFA on the French treasury.
African countries using the CFA could obtain foreign exchange easily and were offered a degree of regional integration. The high fixed exchange rate meant that French imports were relatively cheap - Gabon consumes more champagne per head than Sweden, for example. For countries with low export levels such as Burkino Faso and Senegal, the high exchange rate was very advantageous, but for countries such as Ivory Coast, which export commodities that are falling in value, the high exchange rate was a disaster. When rumours of devaluation began in the middle of last year there was a huge outflow of funds.
Devaluation will hit the poorest hardest and many African governments have warned of civil unrest and asked for special help from the World Bank and other donors to cushion the effect on the urban waged population and the poor.
French business clearly benefited from the CFA and discouraged competition in Africa from businessmen from other countries. According to the president of the club of French investors in Africa, the devaluation will put in doubt the viability of up to 15 per cent of their subsidiaries. But the chief advantage to the French government, or at least the presidency, has been political. With 14 African countries clinging to its skirts, France could claim to be a world power with an influence far beyond Europe.
Yet a self-aggrandising vision does not fully explain the extraordinary relationship between the French government, and in particular President Mitterrand, and Francophone African leaders. It was often direct and personal and excluded the French Foreign Ministry. For many years French Africa policy was under the direction of the President's son, Jean-Christophe Mitterrand - a family touch appreciated by African leaders. There have also been implications for French domestic politics since many African leaders make substantial donations to the campaigns of French political parties.
This system is now coming to an end. Ever since the victory of the French right in March, the government in Paris has adopted a new, more hard-headed, approach to Africa with no special treatment for its old friends. A recent policy statement said bluntly that from now on the key condition for aid was that developing countries should put their economies in order and France would insist that its aid yielded concrete results.
Pressure for devaluation of the CFA has come particularly from the IMF and the World Bank. The French government neatly dodged the dilemma of having to choose between its friends and its principles by announcing that devaluation was up to the 14 governments. Until now it has said it would continue to support the CFA at 50 to one. At the same time Paris said that it would reward those countries which adopted economic structural adjustment programmes approved by the IMF. The IMF, however, would not approve a programme for any country with such an artificially high currency. After that, devaluation was only a matter of time.