• A Bar at the Folies-Bergère, 1881-82, the Courtauld Gallery, London

Manet’s oil sketch for A Bar at the Folies-Bergère was auctioned last Wednesday night at Sotheby’s Impressionist and Modern Art summer sale. The large Salon painting has been at the Courtauld since 1934, but the privately owned sketch was last on sale 21 years ago, when it went for £4 million. This year, its value was estimated at between £15 and 20 million. It was sold in a few seconds for £15 million, plus £1.9 million in fees. (The overall total for the night was £178,590,000, twice as much as last summer’s sale.) Auctions have been described as ‘tournaments of value’ but there was no jousting; the sale was settled between the seller, the buyer and Sotheby’s before the bidding began, and the auctioneer brought down the hammer after just one bid.

‘The big project of the art market over the last twenty-five years,’ Robert Hughes wrote in 1984, ‘has been to convince everyone that works of art… offer such dramatic and consistent capital gains along with the intangible pleasures of ownership – what Berenson might have called “untactile values” – that they are worth investing large sums of money in. This creation of confidence, I sometimes think, is the cultural artefact of the last half of the 20h century, far more striking than any given painting or sculpture.’ Every second of Sotheby’s video of the sale bears out Hughes’s observation.

Sotheby’s renamed the picture for the sale: Un bar aux Folies-Bergèrebecame Le Bar Aux Folies-Bergère, as if there were only one bar at the theatre. Léon Leenhoff, Manet’s stepson, explained in 1883 that the sketch was the ‘first idea for the picture. It is the bar on the first floor, to the right of the stage and the proscenium. Was painted in the summer of 1881.’ The auctioneers might as well have gone a step further and called it ‘That Bar at the Folies-Bergère’.

For the five days before the auction, Sotheby’s galleries had something of the Folies-Bergère about them. ‘We need publicity, daylight, the street, the cabaret, the cafe, the restaurant,’ Alfred Delvau wrote of Paris in the 1860s. ‘We like to pose, to make a spectacle of ourselves, to have a public, a gallery, witnesses to our life.’ Auction houses are like those cafes and theatres, and if ever there was a picture that depicts the ambiguities associated with the idea of the sale, it’s Manet’s bar – what is the bartender selling, and does it include herself, as T.J. Clark argued in The Painting of Modern Life? – and there aren’t many better places to observe the ambiguities associated with selling than an auction house. There were no bars, no bartenders, no hats, no acrobats at the Bond Street galleries, but bourgeois London promenaded through them, looking at and overhearing one another, taking in the out-of-this-world prices. A man who I was told had made a fortune from rubber bullets posed for a photograph next to Degas’s Petite Danseuse de Quatorze Ans.

Unlike the atmosphere at the National Gallery, there’s constant chatter at an auction house. You can’t help talking about the money involved, or avoid overhearing auction-house staff talking up their pictures to clients. Erving Goffman wrote about the advantages of being posh in Interaction Ritual:

Folklore imputes a great deal of poise to the upper classes. If there is truth in this belief it may lie in the fact that the upper-class person tends to find himself in encounters in which he outranks the other participants in ways additional to class. The ranking participant is often somewhat independent of the good opinion of the others and finds it practical to be arrogant.

In contemporary auction houses that idea of class is less apparent; the people who work there give the impression of being posh, but the buyers walking through the galleries are more ambiguous; you can’t tell whether the man in the jeans is a tycoon, or if the woman in a suit is a CEO. In Manet’s two paintings, the men have the money, and they’re all dressed the same, but by today’s standards they look as if they work for someone else. In contemporary London, the rich give the appearance of working for no one but themselves.

In the sketch and the painting, there is one bar, but two different barmaids, and two different men, standing to the right in each picture. Only one figure is seen directly, rather than as a reflection in the large mirror in the background, and that’s the bartender: seen from the front and (in the mirror) from the back, she is a double presence in a setting full of confusion and ambiguity. In the sketch, she looks to her left, while the customer looks up to her; in the painting, she looks out, while the gent appears to stare over her shoulder at the reflection of a women in white in the front row of the balcony – the complex geometry of the picture, and who is looking at who and how, is explained by Malcolm Park. Manet’s brother Eugene said of the making of these paintings: ‘He is creating a painful fiasco for himself at the [Salon] Exhibition. He is always redoing the same painting: a woman in a café.’ She doesn’t look unlike an auctioneer.

On the first day the sketch was on show at Sotheby’s, I went to see it with a Manet expert who wanted to have a look at the edges of the painting obscured by the frame. A man wearing a black apron appeared with a drill; he unscrewed the protective clear plastic backing to the picture, and the frame came off. The sketch for A Bar at the Folies-Bergèreis a small painting even with its frame; without it, it looks smaller still, but the detail – the bottles in the foreground, the men and their top hats in the background at the top left – is outstanding.