The French take over the leadership of the Group of 20 this autumn, a prospect that must be exciting Downing Street and the White House already. Last week Nicolas Sarkozy, France’s president, set out his priorities, initially to a complaisant audience of French ambassadors in the safe environs of the Quai d’Orsay.

He proposes to be an activist chairman. Who could have imagined otherwise? France’s leadership will be energetic and effective. In particular, it will promote fundamental reform of the international monetary system, a theme Mr Sarkozy broached in his address to the World Economic Forum in Davos in January. Instability in financial markets, he argued, “is a threat to world growth”, adding: “We need new instruments to prevent excessive currency volatility.” What the full range of those instruments might be was not set out, but he did call for a new reserve currency “not issued by one country alone”.

There are the germs, here, of yet another narrative explaining the financial crisis and its aftermath. Mr Sarkozy has already been fertile in his explanations. Initially, we may recall, the French focused on hedge funds and on offshore centres, known more colourfully in French as “fiscal paradises”. In the run-up to the London G20 last year, indeed, Mr Sarkozy insisted on measures to clamp down on them – threatening not to show up at all if Gordon Brown, Britain’s then prime minister, did not concede the point. We hear little of those concerns now: the caravan has moved on.