A day after his inauguration, French President Emmanuel Macron headed to Berlin to meet German Chancellor Angela Merkel, as the two leaders seek to reinvigorate the Franco-German relationship and the troubled European project that it underpins.

With Germany's economy, Europe's largest, outperforming that of France, the traditional Franco-German motor at the heart of the EU project has begun to misfire. Merkel and Macron want to kick-start ties with an alliance some German media have dubbed "Merkron." Europe's "Franco-German motor" has often worked best in the past when the leaders of opposite political persuasions have been in power.

Over the weekend, Merkel said she wanted close cooperation with Macron and that their two countries would do everything to shape European policy. However, her ruling coalition is at odds over how to respond to his calls for closer EU integration.

Macron, who was inaugurated last Sunday, will ram home the message that the European Union is resilient, despite Britain's vote to leave and a spate of financial and migration crises that have boosted the far-right across the bloc.

Germany warned France's President Macron to hold off on his push for radical EU reforms, saying that far-reaching action requiring treaty changes was currently "not realistic."

Macron has said he favors setting up a separate budget for the eurozone, the 19 countries that use the common currency, and also proposes giving the bloc its own Parliament and finance minister.

"A major change with a eurozone finance minister and the budget would require a change in the EU's main treaty," said Friederike von Tiesenhausen, finance ministry spokeswoman. Amending the treaty would require approval from all 28 countries within the bloc. "Which is at the moment not realistic," she said.

"There is an agreement within the government that, given the difficult situations we in Europe are being confronted with, a plan with treaty changes is not a good idea," Foreign Ministry spokesman Martin Schaefer also said.

While relieved that Macron prevailed over far-right leader Marine Le Pen, German media sources have since begun warning that the EU reforms championed by France's new leader could be costly for Germany.

Saturday's edition of Der Spiegel weekly featured a picture of Macron with the headline "Expensive Friend." Hours ahead of Chancellor Angela Merkel's meeting in Berlin with Macron, her spokesman Steffen Seibert said one should not read too much into the alarmist headlines.

Many conservatives around Merkel, fearful the eurozone could develop into a "transfer union" in which Germany is asked to pay for the struggling states that resist reforms, are skeptical of Macron's calls for closer integration.

Last week, Foreign Minister Sigmar Gabriel of Germany's center-left Social Democratic Party (SPD) – a junior partner in Merkel's coalition – accused Finance Minister Wolfgang Schaeuble of the Christian Democratic Union (CDU) of trying to "torpedo" Macron's EU reform plans for political reasons ahead of Germany's election in September.

Gabriel was reacting to comments from Schaeuble suggesting that Macron's idea of creating a budget and finance minister for the eurozone were unrealistic because they would require politically thorny changes to the EU treaty.