* STOXX 600 down 0.2 pct
* Autos stocks dented by weaker French car registrations
* Mining sector back up, builds on impressive run
* IAG deal to buy Niki assets weighs on Lufthansa
* Wednesday's MiFID launch in focus (Adds details, updates prices at close)
By Helen Reid and Kit Rees
LONDON, Jan 2 (Reuters) - European stocks faltered at the start of the trading year on Tuesday as autos stocks fell and strength in the euro weighed, while trading was cautious ahead of the launch of a major reform of European Union financial markets.
The pan-European STOXX 600 index dipped 0.2 percent, as did euro zone stocks.
Autos stocks were 0.1 percent lower, 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.
Schaeffler fell 4.9 percent, while BMW and Volkswagen were both around 0.5 percent lower, recovering early losses slightly.
Basic resources stocks also bounced back from early declines with the sector index rising 1.2 percent.
The mining sector built on the five-year high it reached at the end of last week, riding a wave of rising copper and other base metal prices.
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.
More broadly, trading volumes in European equities remained muted as traders came back from holidays and ahead of the launch of new rules for the region's financial markets.
In other eye-catching moves, Lufthansa slipped 1.4 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 10 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 2.6 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 and Ed Osmond