* STOXX 600 down 0.3 pct
* Autos stocks dented by weaker French car registrations
* Mining sector reverses after impressive run
* IAG deal to buy Niki assets weighs on Lufthansa (Updates prices, adds detail, quotes)
By Helen Reid
LONDON, Jan 2 (Reuters) - European stocks faltered at the start of the trading year on Tuesday as autos stocks fell and an impressive run-up in metals and mining stocks reversed, while strength in oil companies and banks was not enough to stop the slide.
The pan-European STOXX 600 index dipped 0.3 percent in early deals, while euro zone stocks fell 0.4 percent.
Autos stocks sank 2 percent, set for their biggest daily fall since July last year, dented by weaker car registrations data.
New car sales in France fell 0.51 percent in December and the share of new diesel cars dipped below 50 percent for the first time since 2000.
A trader also pointed to a report in Britain's Daily Telegraph citing forecasts that UK car registrations data, due out on Friday, would show a 5 percent decline in new car sales.
Fiat Chrysler, BMW, Peugeot, Renault and Volkswagen were all among top fallers, down 2.4 to 2.8 percent.
Basic resources stocks also fell back, with the sector index down 0.8 percent.
The mining sector had surged to a five-year high at the end of last week, riding a wave of rising copper and other base metal prices, but Tuesday's dip suggested investors were taking profits after a strong run.
Oil, which marked its highest start to the trading year since 2014, supported benchmarks with oil majors across the region rising in concert with crude. Statoil and Total were among the strongest gainers.
Financials also rose, led by Santander, Unicredit and Credit Agricole among top banking stocks.
In other eye-catching moves, Lufthansa slipped 6.3 percent after British Airways owner IAG agreed to buy Air Berlin's insolvent Austrian airline Niki.
The German carrier had backed out of a deal to buy Niki's assets in mid-December due to competition concerns.
"The circa 20 planes not acquired through Niki are a loss but not significant for the Lufthansa investment case from our point of view," said Bernstein analysts.
Germany-listed shares in South African retailer Steinhoff surged 12 percent to the top of the STOXX, despite the firm saying its 2015 results would also have to be restated. The company also said its internal review of accounting irregularities was progressing.
Broker moves also drove trading: an upgrade to "buy" from Sydbank sent wind turbine maker Vestas Wind up 2.4 percent after the company secured several new orders.
The Danish bank said a flurry of new orders and less uncertainty in the U.S. market indicated activity in 2018 could be higher than expected.
(Reporting by Helen Reid; Editing by Matthew Mpoke Bigg)