France’s new president, Emmanuel Macron, has called for a “historic reconstruction” of Europe, saying it is “the only reaction” to fight populism.

Speaking in Berlin on the first full day of his presidency, he was joined by German Chancellor Angela Merkel.

She said the pair had a “joint conviction” that they needed to “deepen the European Union”.

Both said they would work together more closely on defence, eurozone reform and reducing bureaucracy.

Mrs Merkel said the EU depended on France being strong, and that she and Mr Macron had a “joint conviction that we are not only going to deal with the British exit from the European Union, but we also need to deepen the EU”.

She also made her most positive comments yet about eurozone reforms mooted by Mr Macron, saying it may be possible to change EU treaties as would be required to enact them.

“From the German point of view, it’s possible to change the treaty if it makes sense,” she said. “I would be ready to do this, but first we will work on what we want to reform.”

There was a warm welcome for the new French president both from Angela Merkel and – unusually – a crowd singing and dancing outside the chancellory.

In part that’s because Berlin is overwhelmingly relieved that it’s not Marine Le Pen walking up the red carpet. But it’s also because, in Mr Macron, Angela Merkel has a counterpart with whom she shares a desire to reshape the European Union following Britain’s departure.

There is a genuine hope here that the French-German relationship, once so fundamental to the European Project, can be rekindled.

But some of Mr Macron’s ideas about economic reform have raised eyebrows in Berlin – in an election year Angela Merkel won’t risk anything which voters might perceive as a German bailout of struggling member states.

And, despite the smiles on Monday, Mr Macron has yet to prove himself. Berlin expects him to succeed where others have failed; deliver his election promise and kick start the French economy.

Mr Macron wants to create a common eurozone budget, parliament and finance minister.

He denied being in favour of making all countries that use the euro liable for other individual countries’ existing debt.

In other developments:

Mrs Merkel said she was open to Mr Macron’s proposal for a “buy European act” that would stop non-EU companies bidding for public contracts inside the EU
Mr Macron pledged to implement social, educational and economic reforms in France, saying his was the only big EU country that had been unable to avoid mass unemployment
Conservative Edouard Philippe, who is not from Mr Macron’s party but from the centre-right Republicans, was appointed as French prime minister, to mixed reaction