When Emmanuel Macron last visited Berlin in January, he was seen as a long shot to win the French presidency, and couldn‘t even get a meeting with Chancellor Angela Merkel.

On Thursday, the 39-year-old former investment banker returns to the German capital as the election frontrunner, with a promise to reinvigorate the Franco-German relationship and rehabilitate a European Union hobbled by Brexit, Donald Trump and a tide of anti-EU populism.