* FTSEurofirst 300 up 0.4 percent
* Index firms ahead of German Ifo number
* Volumes expected to be thin as investors await taper decision
* Energy services sector falls after Technip profit warning
By Alistair Smout
LONDON, Dec 18 (Reuters) - European shares rose on Wednesday, rebounding from the previous session's falls, with investors positioning for a German sentiment figure expected to show that optimism over the economy is returning.
Volumes were expected to be light, however, with investors wary of being overcommitted ahead of a U.S. Federal Reserve decision that could see the central bank slow, or "taper", its open-ended asset purchase programme.
Investors were betting on a strong reading for the Ifo German business morale survey, due to be published at 0900 GMT, after the ZEW gauge of German analyst and investor sentiment surged far more than forecast on Tuesday.
"There's bias on the upside after the ZEW number yesterday. The German recovery remains on track and data backs the Bundesbank's view of a strong winter half," Ioan Smith, managing director of KCG Europe, said.
"(However), developments across the euro zone remain uneven... which together with the very low inflation environment will keep the ECB open to further easing measures."
Markus Huber, senior sales trader at Peregrine & Black, said that he expected the Ifo figure to come in above expectations, like the ZEW index did, reflecting a stronger economy.
The FTSEurofirst 300 was up 0.4 percent at 1,253.09 at 0816 GMT after falling 0.8 percent in the previous session, and is up 0.9 percent on the week.
However, the current December could be the first in five years to see a drop in the FTSEurofirst 300, which is currently down 4 percent on the month.
Traders said that a small likelihood of a slowing of asset purchases from the Fed was now baked into the price, despite the consensus remaining that the central bank would not act this year, meaning that investors would not want to be caught short ahead of the decision.
"The general view is that for most part people aren't expecting the Fed to taper, but I doubt we'll get too big a move ahead of it," said Nick Xanders, who heads up European equity strategy at BTIG, adding that sentiment would support slight gains in stocks until the meeting.
"Everyone was long going in to December 1, hoping for a Christmas rally, and got caught out. You've got a few people cutting their positions now but I think for the most part people are still more positive than negative."
Weighing on the index were energy services firms, led by Technip, down 7.8 percent after issuing a profit warning, the latest in a string of poor updates from the sector.
The news hit other oil and gas services firms such as Subsea , down 2.8 percent, Petrofac, down 1.2 percent, and Saipem, down 0.9 percent