Standing side by side at a war memorial in Ottawa, two leaders prepared to lay a wreath in honour of their countries’ fallen soldiers. The Canadian, Justin Trudeau, was once one of the West’s youngest leaders. The Frenchman, Gabriel Attal, is France’s youngest modern prime minister. As he stepped forward the 35-year-old Mr Attal glanced, more than once, at his elder counterpart for protocol cues. On his first official trip outside Europe, the fresh-faced French leader was on full display and did not want to put a foot wrong.