* FTSEurofirst 300 down 0.1 pct, Euro STOXX 50 down 0.5 pct
* Investors book recent lofty gains on defensive sectors
* Sanofi turns ex-dividend, weighs on France's CAC 40
PARIS, May 9 (Reuters) - European stock investors cashed in on recent lofty gains on defensive sectors such as pharma and utilities on Thursday, knocking shares from multi-year highs.
Bucking the trend, Spanish oil group Repsol rose 1.2 percent, lifted by results showing a forecast-beating 47 percent jump in adjusted net profit.
At 0745 GMT, the FTSEurofirst 300 index of top European shares was down 0.1 percent at 1,228.03 points, slipping from a near five-year high hit on Wednesday, while the euro zone's Euro STOXX 50 index was down 0.5 percent at 2,771.87 points, retreating from a near two-year high.
Technical momentum indicators have been signalling that the two benchmark indexes were ripe for a retreat.
"We're seeing excessive optimism, with more and more retail investors turning bullish, which is never a good sign," said Guillaume Dumans, co-ahead of 2Bremans, a Paris-based research firm using behavioural finance to monitor investor sentiment.
Pharmaceutical stocks edged lower, taking a breather after the sector surged more than 20 percent in the past six months.
AstraZeneca fell 0.5 percent while Sanofi fell 1.2 percent as it was going ex-dividend on Thursday, after which investors will no longer qualify for the latest dividend.
The drop in shares of Sanofi, Paris's biggest stock by market capitalisation, weighed on the CAC 40, which was down 0.7 percent.
Other defensive stocks also retreated, with German utility E.ON losing 0.9 percent and UK telecom operator Vodafone down 0.5 percent.
The FTSEurofirst 300 and the Euro STOXX 50 have risen about 7 and 9 percent respectively over the past three weeks on the back of strong support from central banks.
"The mood seems quite positive, and we're seeing inflows into equities mostly due to the strong liquidity, but with no visibility on the macro front and no signal that Europe might be turning the corner in the next 9 to 12 months, this rally is fragile," a Paris-based equity trader said.
Volume may be lighter than usual. Swiss, Austrian and Nordic markets are shut for national holidays.