* Beiersdorf says uncertainties in China, Europe remain
* CEO Heidenreich says satisfied with first quarter
* Shareholders criticise share sale by Heidenreich's wife (Adds more comments from CEO, shareholders on share sale)
HAMBURG, Germany, April 18 (Reuters) - Germany's Beiersdorf said its Nivea brand stole business away from rivals in a tough Chinese market for the first time in years in 2012.
Chief Executive Stefan Heidenreich predicted Beiersdorf would post further market share gains around the world this year and said the group still aimed to improve 2013 sales and earnings from a year earlier.
Beiersdorf sees group sales outperforming the market this year, while its margin on earnings before interest and tax (EBIT) will improve from 12.2 percent posted for 2012.
"We are satisfied with the first quarter, although uncertainties in China and Europe remain," Heidenreich told Reuters ahead of addressing shareholders at the group's annual general meeting.
Heidenreich, whose no-nonsense management style was reflected in the brevity of his 13 minute speech, said that there was more work ahead for Nivea in China. The brand is seeking to improve the popularity of its products there, which include face creams, deodorant and suntan lotion.
Heidenreich has implemented a turnaround at Beiersdorf, putting the focus back on its core Nivea brand and coming up with new products, such as Nivea Invisible Black & White deodorant, and La Prairie Skin Caviar liquid Lift, in order to win back market share.
While Heidenreich won praise for achieving faster than expected results from the programme, known as the Blue Agenda, shareholders tackled him over a sale of shares by his wife in February.
She had purchased shares in April 2012 after her husband took the CEO role, and sold them after a 33 percent rise in the share price, making a gain of almost 2 million euros ($2.61 million).
"It was a bad signal to the market in the middle of the Blue Agenda to carry out such a large transaction. False conclusions could be drawn from it," said Steffen Kraus from shareholder rights group DSW to applause from the 800 shareholders present.
Heidenreich did not respond to the comment. Supervisory board chairman Reinhard Poellath said that the transaction was a matter for Ellen-Brigitta Heidenreich. "But it was clearly a good decision to buy the shares at that point," he said.
($1 = 0.7668 euros) (Reporting by Victoria Bryan and Jan Schwartz; Editing by Maria Sheahan and Elaine Hardcastle)