Paris - European shares were flat in early trading on Friday, taking a breather following a brisk two-week rally, with investors turning cautious ahead of a speech by U.S. Federal Reserve Chair Janet Yellen.

At 0730 GMT, the FTSEurofirst 300 index of top European shares was up 0.04 percent at 1,355.66 points, after gaining 2.3 percent in the past four sessions, set to record its biggest weekly gain in six months.

Yellen is due to speak later in the day at the annual gathering of central bankers in Jackson Hole, Wyoming. Investors will be looking for any fresh signals about the timing of U.S. interest rate increases.

Minutes from the Fed's July meeting on Wednesday showed policymakers debated whether interest rates should be raised earlier given a surprisingly strong job market recovery.

The FTSEurofirst 300 has risen 4.5 percent since a low hit two weeks ago, regaining ground following a sell-off triggered in June by worries over the crisis in Ukraine.

But despite the sharp two-week rally, the index is still down 3.2 percent from a 5-1/2 year high hit in June.

“European indexes are halted by big resistance levels. At this point, investors should think about hedging their portfolios, even if the U.S. market continues to rally,” Aurel BGC chartist Gerard Sagnier said.

The euro zone's blue-chip Euro STOXX 50 index was flat, at 3,125.34 points. In the first minutes of trading, the index tested a key resistance level representing its 200-day moving average, before slightly retreating.

Around Europe, UK's FTSE 100 index was up 0.1 percent, Germany's DAX index up 0.1 percent, and France's CAC 40 down 0.1 percent.

On Wall Street on Thursday, the S&P 500 ended at a record high after a flurry of positive economic data, including existing home sales jumping to a 10-month high and initial jobless claims dropping sharply.

Shares in European banks featured among the top gainers, with Deutsche Bank up 1.5 percent, Credit Agricole up 0.9 percent and UniCredit up 1 percent.