The German and French leaders have started working towards what French President Emmanuel Macron said would be an "ambitious, clear road map" for Europe's future, months after he first laid out his proposals for reforming the EU.
Macron hosted German Chancellor Angela Merkel on her first trip abroad after she was sworn in for a fourth term this week, ending months of post-election political drift in Germany.
The leaders showed solidarity with Britain after the nerve agent attack on former Russian spy Sergei Skripal and his daughter.
Merkel said the EU was looking for "the most appropriate response".
Germany and France have long played a key role as leading powers in the EU, which Macron wants to reform dramatically, along with the euro.
Macron said a new vision for Europe was "indispensable" as the continent faced mounting populism, seen most recently in Italy's election, and the Euroscepticism highlighted by Brexit.
"We will propose an ambitious, clear road map" covering everything from defence to migration to education and culture, Macron said ahead of a dinner with Merkel.
EU leaders are to hold their next summit next week.
Macron laid out his proposals in September at the Sorbonne University, calling Europe slow, weak and ineffective.
He proposed a joint budget for countries sharing the euro currency that would allow investment in European projects and help stabilise the eurozone in case of economic crisis.
[timgcap-French President Emmanuel Macron, left, welcomes Chancellor Angela Merkel prior to their meeting at the Elysee Palace in Paris, today. (AP Photo/Francois Mori)]MerkelMacronMarch2018_large.jpg[/timgcap]
He suggested greater harmonisation of EU tax policies - notably on corporate taxes, and taxing internet giants where they make money and not where they are registered.
To deal with Europe's migrant influx, Macron wants a European asylum agency and standard EU identity documents, and in defence a shared European military intervention force and defence budget.
Germany has yet to respond in detail because it had a caretaker government for several months until this week.
"We're not always of the same opinion, but I think we can advance together," Merkel said.
"It's more necessary than ever."