The euro could become the world's leading currency in the next decade if leaders of the single-currency bloc succeed in tightening fiscal integration, European Central Bank policymaker Christian Noyer said in an article to be published in the Journal du Dimanche.

European leaders struck a historic deal at an emergency summit in Brussels on December 9 to draft a new treaty for deeper economic union, in an attempt to stem the debt crisis that is threatening to cause the collapse of the single currency.

The news temporarily calmed markets. But concerns quickly resurfaced as the final details of the agreement have yet to be determined and a new treaty could take up to three months to negotiate.

Ratings agency Fitch has said it doubts a comprehensive solution to the crisis can be found and urged more decisive action from the ECB.

If we implement all the decisions taken at the Brussels summit we will emerge stronger, Noyer said in the article, due to be published to coincide with the 10-year anniversary of the euro on January 1.

In 10 years, maybe the euro will be the world's number one currency.

Noyer, who is also governor of the Bank of France, waxed lyrical about the merits of the euro, saying it had protected purchasing power, improved trade and competitiveness and made workers increasingly mobile.

In the past decade, the euro had become the world's second reserve currency after the dollar, and the only eurosceptics were outside the monetary union, he said.

Contrasting with Noyer's nostalgia, an opinion poll also due to be published in Sunday's Journal du Dimanche showed 50 percent of French people thought the single currency had been a bad idea, compared with 35 percent who approved.

A separate article in Saturday's Le Parisien showed the price of an average shopping basket had risen 22 percent since the euro first came into circulation, with certain basic goods such as the baguette rising up to 30 percent.

(Reporting By Vicky Buffery)