The falling dollar has been an elixir for American companies that have come to rely on sales overseas. For example, Nike, which now gets 60 %of its sales outside of the United States, said that the weaker dollar had increased its worldwide revenue by 3 % in the past quarter.

But what is giving a lift to American multinationals has become a millstone for European companies competing in the United States.

Take BMW, which announced in August 2007 that its second-quarter earnings fell by 4.6 percent as sales in the United States were eroded by the weaker dollar. German car manufacturers compete against companies in Japan, whose currency has not risen as much as the euro has, as well as against Detroit. BMW has not recently raised its prices in the United States, but it may have to as its profit margins come under increasing pressure.

With the euro having recently risen to the 1.47 - 1.49 range versus the dollar, the exchange rate has "attained a pain threshold for European companies,'' according to the president of the European business lobbying group, BusinessEurope.

The problem for European companies is twofold: they must remain competitive with United States companies abroad, and they must continue to lure consumers within the United States, a country that is not only the European Union’s single largest market but also one battling sluggish growth.

It's not easy to hold the line on prices, as any seller of French wine, Italian suits, German cars, or Spanish olives can attest. Economic conditions call for a rise in prices of European goods, but that collides with the need to remain competitive. That tension can be felt at any store importing from Europe.