* FTSEurofirst 300 down 0.5 pct, Euro STOXX 50 down 0.6 pct
* Sanofi, Shell, BNP, Inbev rally after posting results
* Argentina's default weighing on Spanish stocks
By Blaise Robinson
PARIS, July 31 (Reuters) - European shares fell in early trade on Thursday, led by Adidas after the group warned about business in Russia, while Argentina's default also rattled investors.
Shares in the German sportswear company sank 12 percent, dragging Germany's DAX 1 percent lower, after saying it will scale back plans to expand in Russia and overhaul its golf business, as problems in both areas prompted it to slash its outlook for the year.
Spanish stocks also underperformed, with Madrid's IBEX dropping 1.5 percent, as traders cited worries over Spanish companies' exposure to Latin America after Argentina's debt default.
The country defaulted for the second time in 12 years on Thursday after hopes for a midnight deal with holdout creditors were dashed.
Overall on Thursday, corporate results from European blue-chips were relatively positive, with shares in Sanofi surging 3.5 percent after the French drugmaker raised its full-year profit forecast while Royal Dutch Shell stock gained 3.4 percent after reporting a 33 percent increase in quarterly earnings, beating analyst forecasts.
"Despite some decent earnings from a number of blue-chips, the market is stuck in a range, with many negative catalysts including Argentina's default at the forefront of investors' minds," said Lionel Jardin, head of institutional sales at Assya Capital, in Paris.
About 40 percent of STOXX Europe 600 companies have reported results so far in the earnings season, of which 55 percent have met or beaten profit forecast, according to Thomson Reuters StarMine data.
On average, quarterly profits are up 7.1 percent year-over-year, data shows, but revenues are down 1.5 percent, fuelling concerns over the earnings trend.
At 0812 GMT, the FTSEurofirst 300 index of top European shares was down 0.5 percent at 1,359.23 points, after losing 0.5 percent on Wednesday.
Around Europe, UK's FTSE 100 index was down 0.04 percent, Germany's DAX index down 1 percent, and France's CAC 40 down 0.5 percent. The euro zone's blue-chip Euro STOXX 50 index was down 0.6 percent.
Shares in France's BNP Paribas added 0.9 percent after the lender, recently hit by a U.S. fine, reported robust underlying result signalling that clients had not been scared off by the affair.
"Results are above expectations at the operating level. Almost half of the outperformance is derived from capital markets," a Paris-based trader said.
"Corporate financing is doing better than expected too and better than the second quarter of last year. This suggests that the impact of the U.S. litigation is not that large, at least for the time being, so the reputational risk is not yet visible."
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up
Editing by Janet Lawrence