“We can talk about whether you make 2 or 3 percent more debt, or 1 percent, or, like us, a balanced budget,” Ms. Merkel said this week. “But one really must question whether we can go on receiving less than we spend, so that our debts keep on growing. Indeed, a whole crisis of confidence has grown out of that.”

Still, she hinted she could be more flexible if countries undertook reforms to revive competitiveness. Spain, which adopted more business-friendly labor laws and other structural changes to its economy, is one of the few eurozone countries to show signs of recovery. In a visit this week with Prime Minister Mariano Rajoy, Ms. Merkel praised Spain as a model for how to rebound from the crisis.

Ms. Merkel has remained unmoved by her critics, even as Germany’s economy has slowed and been challenged by new pressures like the confrontation with Russia over Ukraine. To some degree, the slowdown in Germany is being driven by a lack of demand for its exports from neighbors like France and Italy, which, lacking the ability to use government spending to spur growth, have struggled to gain economic traction. Italy, the third-largest eurozone economy, has returned to recession and remains saddled with a debt equal to 136 percent of gross domestic product, the highest ratio in the eurozone after Greece. Analysts said a new crisis in Italy could reignite fears that the eurozone will come apart.

Germany is further vulnerable to the strife in Ukraine. Sales of machinery to Russia, the industry’s fifth-largest export market, fell 19 percent in the first six months of the year. On Thursday, Ms. Merkel said the European Union would discuss tougher sanctions this weekend, hours after Kiev accused Moscow of a fresh incursion.

Germany is also grappling with its strained relationship with France, where Mr. Hollande is having trouble holding his party together as calls increase to challenge the supremacy of German economic policy leadership. While the two recessions that have hit France in the last five years have not been as deep as those in other countries, growth has failed to revive meaningfully.

Germans worry about the imbalance between the Continent’s two essential powers, while French leaders feel belittled by Ms. Merkel, who “wants to give us lessons,” said Jean-Christophe Cambadélis, a prominent French Socialist. “We are a great nation trying to pull ourselves together. We are not one of the German länder,” he added, using the German word for its 16 states.

“Germany is a strong country, but it is too weak to lead the Continent alone,” said Guntram Wolff, a German who runs the Bruegel organization in Brussels. While trade with France is important, their common projects — monetary union, the European Union itself, centuries of shared history — count for much more, he said.