PARIS, Jan 29, 2009 (AFP) - With a Cubist-period Picasso, a Brancusi never seen in public and a rare Eileen Gray designer chair, Christie's has great expectations for next month's sale of works owned by late fashion king Yves Saint Laurent and partner Pierre Berge.

Pierre Bergé and Yves Saint Laurent in 1992 Photo : Pierre Verdy/AFP

"No art-lover anywhere in the world can remain unmoved by this auction," Francois de Ricqles, Christie's France Vice-President, told AFP on Thursday.

Amassed by the high society pair over 50 years, the pieces that once graced their various homes is estimated by the auctioneers at up to 300 million euros (392 million dollars). Along with contemporary oils are antique statues, 16th century silverware and even Chinese relics reportedly snatched from a Beijing palace.

Some experts have suggested the three-day sale starting February 23 could fetch up to half-a-billion euros (654 million dollars).

Berge, YSL's lover and business partner, decided to part with the 733-strong treasure trove after the death of his lifelong companion in June, aged 71.

"I hope that everything we loved so passionately will find a home with other collectors. That is the way with works of art," Berge says in the auction catalogue, adding that he was selling "without regret and without nostalgia."

Among the masterpieces are works by Toulouse-Lautrec, Matisse and Leger, as well as a Mondrian that once belonged to film director Otto Preminger. Saint Laurent paid homage to Mondrian in his now legendary 1965 collection.

"It is an extraordinary collection, however you look at it," said de Ricqles.

Gathered by the pair rather in the style of Renaissance princes, he said, the rare pieces were in impeccable condition and well authenticated and went from modern art through Art Deco furniture to baroque statuettes, enamels and jewellery.

The sheer size of the sale is exceptional. De Ricqles describes it as "a milestone in the history of great auctions."

For the auction to be held inside the vast hall of Paris' Grand Palais, Christie's has printed a five-volume, 1,800-page opus that weighs 10 kilos. Eight auctioneers will work in shifts during the three-day event, with 100 telephone lines installed and seating for 900 buyers.

Christie's has already begun touring, taking 90 of the best pieces to New York in November, currently to London and to Brussels next week.

An early 19th century Brancusi sculpture, estimated at 15-20 million euros (19-26 million dollars), was first acquired by Fernand Leger in exchange for one of his own works and has never previously been on the market.

A brown leather Dragons armchair by Irish architect and designer Eileen Gray is a unique piece estimated at two to three million euros (two to four million dollars).

Despite the global economic meltdown, Christie's has maintained estimations of the value of the works issued last September "largely on par", said de Ricqles. A few have been lowered, such as the Cubist-era Picasso, now valued at 25-30 million euros (32-39 million dollars), or 5-10 million (6-13 million dollars) less.

Chinese lawyers had threatened to sue Christie's over the sale of two bronze animal heads that once adorned the Old Summer Palace, or Yuanmingyuan, and were stolen when Western armies burned the palace down during the second Opium War in 1860.

But the auction house said the 10-million-euro (13-million-dollar) relics would be put up for sale. "We have not received notification," said Christie's.by Fabienne Faur