The creation of the single currency was the culmination of a process that included several attempts to fix the parities between European currencies, which never lasted long and led to frequent devaluations. European countries discovered that, with mobility of capital, a regime of fixed parities was not compatible with each country following an independent monetary policy. The solution was to have a single currency and eliminate the monetary independence of each country. Initially, many of the economists consulted thought that the project of the euro would be a failure. Despite the physical disappearance of the national currencies, the differences between the economies of the euro zone would put the system under new tensions, which could no longer be remedied by means of controlled devaluations. In the face of this skepticism, European leaders were determined that there would nevertheless be a single currency. This was an essentially political decision.

The first ten years of the euro made the negative omens disappear. It was only with the great recession of 2009 that doubts resurfaced. These centered on the ability of sovereign states to meet their debt payments and on the solvency of the financial institutions of the various eurozone countries. For a depositor, a euro deposited in a peripheral country was no longer viewed in the same light as a euro deposited in a German bank.

In response to the fragmentation of the financial system, the idea of a banking union emerged. A banking union implies joint regulation but also joint resolution of possible failures in the financial system, thus opening up a new avenue for fiscal transfers between countries. If a financial institution fails in one country, the other countries will have to pay for part of the bailout. Thus, banking union represents a qualitative leap in the process of European integration. Its fiscal consequences mean that Europe is coming closer from an economic point of view to what we would consider a country. In addition to common regulation and common monetary and exchange rate policy, there is also greater fiscal integration. We will see if Europe moves forward on the path of further integration.