Shares on the French and German stock exchanges fell sharply Thursday, dipping below three percent, over oil price concerns and after Federal Reserve boss Janet Yellen raised concerns about the global economy.

At 0830 GMT, France's main CAC 40 index was 2.57 percent lower, at 3,956.73 points, after falling briefly more than three percent. The DAX fell by 3.3 percent to an intraday low of 8,719.79 points. At 0845 GMT it was showing a loss of 2.6 percent.