A upcoming auction of late French designer Yves Saint Laurent's art collection may have hit a snag, after Chinese officials demanded on Thursday the return of two valuable Qing Dynasty bronzes slated for the sale later this month.

Speaking at a regularly scheduled news conference on Thursday, Foreign Ministry spokeswoman Jiang Yu raised the issue to reporters. She said the two bronze sculptures were "stolen and taken away by intruders," and called for their restoration to China.

The animal-head sculptures — depicting a rat and a rabbit — are part of a three-day Christie's International auction at the Grand Palais in Paris beginning Feb. 23.

After the fashion icon's death in 2008, his longtime companion and business partner, Pierre Bergé, decided to sell several hundred artworks and artifacts, with the proceeds earmarked for an AIDS research foundation he had set up. Christie's has billed the auction as the largest sale of privately owned art ever in Paris.

Christie's documents acknowledge that the two bronzes originally hail from the Chinese zodiac-inspired water fountain at Beijing's former Imperial Summer Palace, which was sacked by European troops in October 1860.

However, responding to China's demands on Thursday, the auction house issued a statement saying that while it "respects the cultural context around the sale of the fountainheads, we respectfully believe the auction will proceed."

The statement also emphasized that each lot in the Saint Laurent-Bergé sale has "a clear and extensive history of ownership."

According to media reports, more than 80 Chinese lawyers have volunteered their services in an attempt to halt the upcoming sale of the two pieces.

Over the years, a number of the original fountain sculptures — designed by Jesuit missionaries and depicting the 12 animals of the Chinese zodiac — have surfaced at auction and in art collections worldwide.

Some, such as the boar and horse sculptures, were purchased by Chinese collectors who then donated them to China's Poly Art Museum. The Beijing museum also holds the tiger, monkey and ox sculptures, which the Chinese government spent millions to recover (also at auction).

Christie's experts have estimated that the rat and rabbit head bronzes could fetch up to $15 million Cdn each. Overall, the Saint Laurent-Bergé sale also includes extremely valuable furniture, drawings, artifacts and artworks, by the likes of Picasso, Goya, Matisse and Mondrian, that the two men amassed over four decades.

With files from the Associated Press