German auction house Grisebach on Friday said it would open a new legal probe into a Kandinsky painting sold for 387,000 euros, after Poland said the work had been stolen from one of its museums.
The 1928 piece called "Untitled" by Russian avant-garde artist Wassily Kandinsky was auctioned on Thursday evening in Berlin at a sale where a painting by German expressionist artist Max Beckmann fetched a record price in Germany.
But Poland's culture ministry said the watercolour was stolen in 1984 from Warsaw's National Museum.
The sale by Grisebach was therefore "highly unethical and contrary to the standards that should apply in the international art market," it said.
"The Minister of Culture and National Heritage will take all possible legal steps to recover the work," it added.
Poland's consul to Berlin, Marcin Krol, said the painting bore "markings clearly indicating its origin from the National Museum in Warsaw" and that any sale following the theft could not be considered an act of good faith.
In a statement, Grisebach said it had carried out authenticity, provenance and ownership checks "with the greatest care with regard to the Kandinsky watercolor".
"It emerged that the painting had been in the possession of the consignors for several decades and had already been sold publicly at auction by Sotheby's in London in the first half of the 1980s," it said.
The auction house added that it had carried out a "further legal investigation" after it was contacted by Polish authorities.
But the probe led to the "clear conclusion that there were no legal objections to the auction of the watercolor."
Nevertheless, the auction house said it would now seek to "bring about a supplementary judicial legal review by a court in order to obtain a binding clarification".
Paintings by Moscow-born Kandinsky, one of the pioneers of modern abstract art, are highly sought after and can fetch millions of euros (dollars) at auction.
