Speaking on France-2 television, Finance Minister Francois Baroin confirmed that France had been lowered by one notch. That would mean a rating of AA+, the same rating the United States has had since S&P downgraded it last August.

Baroin said France had received a change to its rating "like most of the eurozone," referring to the 17 European nations that use the euro currency, but there was no confirmation from S&P that any other nation had been downgraded. S&P had warned 15 European nations in December that they were at risk for a downgrade.

A credit downgrade would escalate the threats to Europe's fragile financial system and raise the costs at which the affected countries — some of which are already struggling with heavy debt loads and low growth — borrow money.