Modern art overshadows some of the masters in several recent auctions.

'Femme assise, robe bleue’: Picasso’s portrait of Dora Maar, which the dealer Ernst Beyeler had owned in the Sixties, went for £18 million Photo: Christie's

Today, Christie’s is selling 100 works of art from Jeffrey Archer’s private collection for an estimated £5 million. Whether the Archer provenance will help them on their way or not remains to be seen. He is, after all, a celebrity, and celebrity does sell.

In the art world, though, he is like a minnow compared with the Swiss dealer Ernst Beyeler. Beginning in 1947, Beyeler built a reputation as one of the foremost dealers in modern art, conducting major transactions of works by Giacometti and Paul Klee, and establishing close personal relationships with Picasso, Lichtenstein and Rauschenberg. His exhibition catalogues read like a Who’s Who of classical modernism. With the art fair he set up, and the foundation he built for his personal collection, he made Basel a focal point for art lovers and collectors.

Beyeler died last year, and pieces from his home and his gallery (as distinct from his foundation) were sold by Christie’s last week as part of the season’s main Impressionist and modern art auctions. The reverence and esteem in which he was held generated two extraordinary prices. The 17th-century Spanish wooden table that was his desk had been valued by Christie’s furniture department at £8,000 and set the sale off at an electric pace as it sold for £289,250. A glass-topped table designed by Diego Giacometti, on which Beyeler kept his fax machine, was estimated to fetch £50,000 and sold for £646,000.

But when it came to the art, the market was generally more discriminating, knowing that Beyeler’s best works were in his foundation. A Giacometti drawing of his biographer, James Lord, was knocked down to the dealer Thomas Gibson for £180,000, below the £200,000 estimate. In 1988, Beyeler bought a Picasso drawing from the collection of Douglas Cooper for a huge £850,000, possibly because of Cooper’s close association with Picasso. Last week it barely recovered that amount – a loss in real terms, and proof that even great dealers can get carried away. An unusually large painting of water lilies by Monet looked unresolved and had not been signed by the artist. Estimated at an ambitious £17 million, it was the only unsold lot from his collection.

The top lot space in the Beyeler sale was left instead to a Picasso painting of Françoise Gilot which sold to New York’s Acquavella Galleries much as predicted for £10.7 million. But this was surpassed by two other paintings of the artist’s lovers from other collections. A small painting of Marie-Thérèse Walter, sent for sale from the University of Sydney, sold for £13.5 million to the London dealer Alan Hobart, bidding for one of his well-heeled clients, and a painting of Dora Maar, which had passed through the hands of Ernst Beyeler in the Sixties, soared above estimates to sell to the Geneva-based collector Dimitri Mavromatis for £18 million.

Also once part of Beyeler’s stock was a painting of a dancing woman by Paul Klee which sold for a record £4.2 million, though whether the Beyeler provenance added to the appeal of either painting, I doubt. The market for great modern art is strong, and was confirmed in the same sale by a rare watercolour of Tunis by the German expressionist August Macke, which quintupled estimates to sell for a record £4 million.

Modern art again led the way at Sotheby’s shorter sale, which contained the highest selling lot of the week in an Egon Schiele townscape of houses and washing lines by a river. Sent for sale by the Leopold Museum in Vienna to pay for Schiele’s Portrait of Wally, which had been subject to a lengthy restitution case, the painting doubled the previous record for Schiele, selling for £24.7 million. A record £4 million was also set for an art deco- style painting of a sleeping woman by Tamara de Lempicka, a big increase, at $6.6 million, on the painting’s previous auction price of $294,000 in New York in 1997.

Demand for Magritte was strong at both sales. At Sotheby’s, the artist’s tiny L’empire des lumières (7x9 in), fetched the second highest price ever for a Magritte watercolour, doubling estimates at £2.4 million. Although there were strong prices for Renoir, whose market seems to be on the rebound, and for the Belgian post-Impressionist Theo van Rysselberghe, 19th-century and Impressionist paintings were overshadowed by the moderns, and are beginning to look cheap by comparison.