For Noir's work, featuring a totem-pole shaped figure with exploding lips and a bulging eye, once sold for millions. How many millions, nobody can tell, but enough to make someone a small fortune. Suffice to say that even the photographer who put together a catalogue of Noir's oeuvre earned DM42,000 (pounds 14,800) on the project. But of that or any other proceeds, the 39-year-old Frenchman has seen nothing.
Admittedly, the painter used the wrong medium. But who was to know in April 1984 that the resilient structure that blotted the view from his window would not survive the decade? That is when he started to decorate the Wall, not so much to create art or make a statement, but to make his Kreuzberg slum habitable. The swirling curves of bright colours were an instant hit, attracting tourists in their thousands to gape at the coolest open-air show on Earth.
A star was born. Graffiti had become a genre, Noir a pioneering artist - founder of a school, no less - and commissions flooded in. In 1985 he was asked to apply his genius to the lavatory of a railway cafe. Two years later he became official wall painter on a Wim Wenders film set. By 1988 he was decorating the emergency exit of Berlin's Gloria cinema. And in all this time, he remained true to his metier, covering two and a half miles of the frontier with "Crocodile Man".
Then came November 1989. All Noir can remember of the euphoria is the ceaseless hammering outside his room - the Wall was five yards from his window. When the structure was finally breached, he rushed out with his spray cans and started painting the other side.
But the hammering never stopped, and soon the bulldozers would join in. His work was literally crumbling in front of his eyes. But then, just as everything seemed lost, a long section in Kreuzberg was rescued from the vandals. The East German authorities, betraying for the first and last time in their history a modicum of business sense, decided to flog the ruins to the decadent West.
The world's biggest mural was cut into 81 segments, catalogued, and put up for sale. Thirty-three of the segments were attributed to Thierry Noir, and 12 to his friend, Kiddy Citny. The auction was held in Monte Carlo in June 1990, and grossed at least DM1.5m. There must be, somewhere, a lot of satisfied Noir collectors, though the artist himself does not own a piece of his creation.
Nor does he have any of the money. It took until 1995 for Noir and Citny to establish their right to the royalties, having sued the authorities all the way to Germany's Supreme Court. By then, unfortunately, the company that had pocketed the receipts had gone bankrupt. So had East Germany and the officials who had organised the auction.
Noir and Citny then turned to the German bureaucrats who are legal heirs to the Communist regime. They discovered that the Finance Ministry had taken over the bank accounts of the abolished East German foreign trade company Limex, which had authorised the sale. The Finance Ministry, needless to say, would not part with a pfennig, so the matter is once again being dealt with by the two sides' learned friends.
"They will not accept that, as artists, we are entitled to be paid," Noir says. "They think we are nobodies; opportunists who simply want to get rich."
It has taken seven years to reach this impasse, and will take several months more to settle the claim. Next March a Berlin court is due to deliver its verdict. The lawyers think the state will have to pay, and the haggling now is over how much. The bureaucrats are holding out for 10 per cent of the DM1.5m, to be split between Noir and Citny, while the artists want the full whack.
"If we win I am going to throw a huge party," Noir promises. But even if he loses, he might still paint the town red.