* Most national indexes fall, FTSEurofirst rises
* Wirecard, Jyske Bank, L&S get results lift
* China weighs on market, mining stocks fall
* RWE hit by broker downgrades (Adds detail, quote)
By Alistair Smout and Lionel Laurent
LONDON, Aug 18 (Reuters) - European equities were steady on Tuesday, with a buoyant set of corporate results offset by the impact of weak trade in Asia and a fall in commodities prices driven by worries over China's growth outlook.
Most major indexes across Europe were in negative territory, with blue-chips in France, Germany and Italy 0.1 percent to 0.3 percent lower.
Britain's FTSE underperformed, down 0.4 percent as sterling strengthened. The sharp foreign exchange move distorted the calculation of the pan-European FTSEurofirst 300 index to leave it up 0.2 percent to 1,533.87 points, despite benchmark indexes being lower.
Traders said volumes were relatively muted in Europe, with under 40 percent of the 90-day average volume traded by 1405 GMT. Surprisingly weak U.S. data released on Monday also weighed on sentiment.
Pan-European equities are down some 7 percent since peaking in April, with Greece's debt drama and jitters over China's move to allow its currency to weaken balanced by the European Central Bank's asset purchase programme and one of the best earnings seasons in five years.
Chinese stocks plunged on Tuesday, reigniting fears that Beijing may be intent on a deeper devaluation of the currency.
Swiss-listed luxury brands Swatch and Richemont , which have substantial exposure to China, fell more than 1 percent, while energy and mining stocks were also hit by a dip in oil prices and weak metals prices.
"We do not consider this policy move to presage a substantial devaluation of the Chinese currency," said Michael Stanes, Investment Director at Heartwood Investment Management.
"We think the markets have overreacted to the move and developments might even afford opportunities in currency and financial markets most exposed to the renminbi's (yuan's) performance."
Outperformers in Europe included Wirecard and Denmark's Jyske Bank, up 7.2 percent and 5 percent respectively after quarterly results.
Swiss chocolate maker Lindt & Spruengli saw its shares hit record highs after better-than-expected earnings.
German utility RWE fell 2.8 percent, with broker downgrades from SocGen, RBC and Berenberg sending the stock to an all-time low.
"Weak power prices and adverse guidance at H1 results drive 20-30 percent cuts to longer-term EPS forecasts... (A) dividend cut also seems unavoidable," analysts at RBC said in a note.
The Athens stock market dipped into negative territory a day before a German parliamentary vote that looks certain to approve Greece's new bailout plan, though a significant minority of Chancellor Angela Merkel's German conservatives are expected to oppose it.
Europe bourses in 2015: link.reuters.com/pap87v
Asset performance in 2015: link.reuters.com/gap87v
Today's European research round-up
Editing by Keith Weir