PARIS — European stocks fell about 2 percent and the euro slipped on Wednesday, as European Union leaders began converging on Brussels for yet more talks on how to address the intensifying Greek crisis and the existential threat to the common currency.


The fear in the market is palpable, leading investors to move euros out of the struggling periphery countries and toward the central economies of Germany and France. In a debt auction Wednesday, Germany sold almost €4.6 billion, or $5.8 billion, of its two-year Schatz notes priced to yield 0.07 percent — the lowest ever; at that yield, investors are essentially handing their euros to Germany for safekeeping, expecting nothing in return.


“There’s a flight to safety inside the euro zone,” Steven Saywell, head of currency strategy for Europe at BNP Paribas in London, said. Beyond that, he added, investors are also buying bonds amid expectations that weakening economic data will soon lead the European Central Bank to cut interest rates again.


The leaders of all 27 E.U. member nations will be present at the early evening meeting, where Chancellor Angela Merkel of Germany and proponents of the austerity-first approach to addressing the crisis will hear proposals from the French president, François Hollande, of how economic growth might factor more into the equation. Mr. Hollande has suggested that euro member nations pool financial resources to make funds available for growth.


Officials are meeting at a time when the possibility of a Greek exit from the euro zone has become a real possibility, one to be discussed openly.


The German central bank, the Bundesbank, warned Wednesday that the Greek situation was “extremely worrying,” and that “Greece would have to bear the consequences” of its actions if refused to implement the agreed austerity measures. In such a situation, the bank said in its monthly report, the challenges for the euro zone and for Germany “would be considerable, but manageable given prudent crisis management.”


The Bundesbank warned against easing Greece’s bailout terms, saying that such a move “would damage confidence in all euro-area agreements and treaties and strongly weaken incentives for national reform and consolidation measures.”


Hermann Van Rompuy, the president of the European Council, has sought to play down expectations of major decisions at what he has billed as an “informal dinner” to prepare for a European Council meeting on June 28-29. But by that date, Greeks will have held their vote in what is being treated as a referendum on whether the country will accept the harsh bailout terms its lenders have demanded as a condition for getting aid.


“The hard truth is that there are no magic solutions to solving this crisis,” the Netherlands’ caretaker prime minister, Mark Rutte, said Wednesday before the meeting. “We will all have to keep our spending in check, pay off our debts and swiftly introduce healthy reforms. This is what will kick-start growth in a highly competitive world, and offer the young a new hope and a future.”


The austerity approach has come under fire because countries grappling with shrinking economies stand to further exacerbate their problems by cutting spending and raising taxes. But Germany and its allies are deeply skeptical of anything that smacks of a return to renewed deficit spending, fearing that needed reforms will be left by the way and that they will be left to pick up the tab.


“I think a damp squib” — a wet firecracker — “is all you can expect from this meeting,” Mr. Saywell said. “Mr. Hollande will propose euro bonds and Frau Merkel will say, ‘No thank you.”’


Italian consumer confidence data for May illustrated the depth of the gloom in Europe. Sentiment in the month fell to the lowest on record amid growing fear about the economic outlook, the national statistical agency, Istat, said.