Admittedly, Mr Fischer still wears jacket and jeans on the floor of the German parliament, the Bundestag (Rudolf Scharping, leader of the Social Democrats, would never be seen without a double-breasted suit). But the change in style is clear - and reflects a crucial change, in German politics today.
More than ever before, a Green party seems to be within reach of taking its place in a national government, in Europe. In Britain and in France there is little room for the environmentalists. But in Germany, things look different. In elections last weekend in North Rhine-Westphalia, Germany's most populous state, 10 per cent plumped for the Greens - twice as many as before. In some areas, the figures were higher still: in central Cologne, almost one in three votes went to the Greens.
Just as the Greens have risen steadily in the polls, so the traditional minority stakeholders in the German government, the Free Democrats (FDP), have continued their miserable fall. After two more electoral disasters last weekend - the latest, in a long line - Klaus Kinkel, the foreign minister and FDP party leader, said that he would not take the easy option of resigning. Whereupon, he duly resigned. His most likely successor, Wolfgang Gerhardt, who officially declared himself a candidate for the post yesterday, seems unlikely to have any magic remedy.
If the FDP's decline continues, then the Greens could become established as the pivot of German politics, like the FDP in the past - with the power to see ruling coalitions come and go.
The Greens' current successes are not entirely a bolt from the blue. Founded in 1980, they gained seats in the Bundestag three years later. Petra Kelly, the de facto leader of a leaderless party, became the best known Green politician in the world.
Throughout the 1980s, however, the party was wracked by the fierce divisions between the "Fundis" and "Realos". The Fundis ("fundamentalists") believed that there should be no compromises, and wanted to stay outside the establishment, loyal to their extra-parliamentary roots. The Realos believed in change from the inside.
German unity in 1990 spelt disaster for the Greens, not least because of their deep lack of enthusiasm for unification; the party failed to be returned to the Bundestag. The death in 1992 of Petra Kelly - shot by her partner, Gert Bastian, who then himself committed suicide - was widely seen as the symbolic end of an era.
But the Greens' return, stronger than ever, suggests that they may be here to stay. Mr Fischer is now known as "the secret opposition leader", not least because Mr Scharping conspicuously fails to do the job. The Green electoral programme still contains demands - for the abolition of Nato, for example - that no German government could seriously be expected to press for. But these are now little more than radical decoration. Not just the Social Democrats, the Greens' most obvious coalition partners, but also leading figures in the ruling Christian Democrats (CDU) have been queuing up to hold friendly talks. For the CDU, after all, the Greens might provide life after the FDP. Both CDU and Greens publicly snort at the idea of a future alliance. But the talks continue.
Part of the reason for the Greens' unique strength in Germany lies in the nature of German society, and - indirectly - in its history. The Greens' concerns include the standard ecological issues: nuclear waste, ozone, the greenhouse effect. Equally importantly, however, the Greens provide an alternative agenda, with emphasis on pacifism, anti-racism, and feminism (women play a much more important role in the Greens than in any other party).
On international issues, too, their profile is high. On Chechnya, for example, the Greens have been more outspoken than the cautious Christian Democrats or Social Democrats. The obvious evils of slavish political obedience, in recent German history, have deeply influenced post-war generations. It has proved an important factor in the Greens' success , with their pre-programmed disobedience.
This natural rebelliousness may prove a problem, in terms of sharing power. It is still unclear whether the Greens can easily become part of a national government, with all the compromises that this would entail.
A headline in the weekly Die Zeit asked, earlier this year: "What do they want, what do they stand for?" The answer, it seems, is changing all the time - and will no doubt change again, if Greens become part of the federal government in Bonn and then Berlin, in the years to come. The party can reinvent itself, any number of times. There is, perhaps, only one bottom line: the desire not to be pigeonholed.Reuse content