Something I have often said as a joke is that Germany realized after World War II that it could never take over Europe militarily, so it switched to trying to take over monetarily. Somehow, that joke always slipped into conversations regarding the European Union and the Euro. I made the joke initially because the Euro was so heavily backed be the German economy and banking system. As it stands now, to join the Euro community, a country must meet the "Maastricht Criteria." These conditions (which include domestic price stability, measurements of responsible public finances, exchange rate, and others) were put in place to insure financial stability amongst the nations involved with the single European currency. Basically, a country subordinates its economic and monetary policy to the wisdom and wishes of the European Central Bank.
While the purpose of the ECB is to maintain stable growth throughout the EU, policy will always favor the major players, in this case, the two largest players in the European economy are Germany and France, with Germany typically leading (of the $18.85 trillion dollar Gross Domestic Product, $3.82 trillion is Germany and $2.98 trillion if France.) Germany and France are also two of the countries that do not follow the economic and public finance guidelines set down as requirements of the member states, specifically the percentage of public deficit and debt allowable(60.7% and 67% public debt respective of GDP, respectively, with the maximum allowed by the ECB set at 60%.) For those interested, or in need of reading material as sleep aids, here is the Maastricht Treaty.
Why do I find it interesting to point all of this out? Russia recently tossed out the idea of proposing a global currency at the next G20 summit. With the Gross World Product at $78.36 trillion and the US economy running a Gross Domestic Product of $14.33 trillion, that puts the United States at 18.3% of the world's economy. Would Russia (GDP of $1.76 trillion, or 2.25% of the world's economy) be willing to subordinate itself to the needs of the largest segment of a globalized economy, or would this proposal turn into a device to institute "parity" in the world's economic systems? With some of the other recent moves by Russia, I would think motivations need to be carefully considered.