There is nothing unusual, either, about the Klaas family themselves: comfortably middle-class, a friendly manner, a Renault 21 (his) and a Renault 5 (hers) in the garage. Nor, in German terms, is there anything surprising about their ecologically perfect kitchen: carefully-washed margarine and yoghurt containers stand on the draining board, waiting to be taken to a recycling point; paper and cardboard are kept separate.
This ordinary German family may, however, indicate a far from ordinary change in German and perhaps even European politics for the months and years to come.
In past years, the family was a politically mixed bag. Ingrid, 54, used to vote for Helmut Kohl's Christian Democrats (CDU). Her son, Robert, voted for the junior partners in the government coalition, the liberal Free Democrats (FDP). His brother, Martin, voted for the opposition, the Social Democrats (SPD). Their sister, Barbara, who voted for the first time last year, supported the Green party. Today all of the family except Franz share one thing in common: they now vote for the Greens - a party which, in Britain, is still seen as a bunch of exotic no-hopers. Franz, the wistful paterfamilias, remains loyal to the CDU.
In doing so, they are part of a clear trend. In a key regional election last month, 30 per cent voted for the Greens in Cologne. In the city's Sudstadt district, where many students live, almost 40 per cent voted Green. In Britain, by comparison, just half a per cent chose Green at the last election.
The Klaas family talk of the complacency of the political establishment when explaining why they transferred their loyalties. Martin, 27, a computer specialist, talks of the "inflexibility" of the SPD. Robert, 25, an economics student, had been loyal to the ailing FDP, who traditionally held the ring between left and right. He is unimpressed by Green economics but he believes the Greens provide "something new".
The youngest member of the family - Barbara, 22, who is training to be a graphic designer - voted for the first time in European and federal elections last year. For her, the two main parties are "unelectable - they are all interchangeable". Hence the Greens get her vote.
The party's successes in Cologne and elsewhere mean that the Social Democrat prime minister in North Rhine-Westphalia - Germany's industrial heartland and most populous state - has had to eat large helpings of humble pie in recent weeks. Johannes Rau had governed with an absolute majority for 15 years and insisted he would not form a coalition with the Greens. Now, he is embroiled in negotiations which probably will lead to just such a coalition within the next few weeks. Many believe that an SPD-Green coalition in North Rhine-Westphalia would be a dress rehearsal for Bonn.
Meanwhile, if the Greens continue to steal votes from the FDP, Mr Kohl, the German Chancellor, will no longer have a coalition partner to do business with. Partly as a result, senior Christian Democrats have been discreetly sniffing out the Greens, regarding future political deals, at a regional and even a national level. Franz Klaas, 55, whilst remaining loyal to the CDU, says that he can "certainly imagine" a future coalition between his party and the Greens. Senior Greens in Bonn suggest mischievously that it would be in the CDU's interest in North Rhine-Westphalia to "make us an attractive offer" - in order to snatch power from the Social Democrats altogether, and create a CDU-Green coalition. The suggestion is whimsical - but not entirely frivolous.
Until recently, the CDU appeared to write off the Greens as a bunch of crazies who would endanger stability if they were ever to get into power. But many of the Greens' most radical proposals - for example, the abolition of Nato - now seem little more than decoration. Even Green supporters sound sceptical about the official policies. Regarding the Greens' ideas on defence and economics, Barbara says: "They're often quite naive. I can't imagine the Greens holding power alone - I wouldn't want that."
Certainly, scepticism about Green economic policies is widespread. The head of the German equivalent of the CBI complained this week, with reference to the growing power of the Greens, that a part Green coalition in Bonn would send a "catastrophic signal" about the economy. Officially, the party is in favour of a standard 30-hour week, and would prohibit anything more than 40 hours a week. They are committed to massive state subsidies for job creation, and there is talk of tough action to reduce the powers of the banks. Some observers believe that the Greens' anti-big business policies may quickly be jettisoned if the party gets within sight of power. In recent months, the Greens have made efforts to woo businessmen; each convert is publicly presented as a great triumph.
Franz Klaas , the CDU die-hard, admits: "They've brought the subject of the environment forward a lot. Without them, neither the CDU nor the SPD would have moved so much." The party - anti-hierarchical and anti- militaristic - is especially successful with female and young voters. Robert talks of the "emphasis on individualism and non-conformism" as one explanation for the success of the party which almost vanished from the political landscape at the time of the euphoria over German unity in 1990, before being reborn in the past two years.
For the moment, the Greens can bask in their new popularity. As they take greater responsibility, their contradictions will, no doubt, become more apparent. But the huge controversy in Germany over Shell's Brent Spar oil rig is a reminder of just how important environmental issues are for Germans. Barbara is confident that the Greens' successes are not just a flash in the pan. "Things can go up and down, but the Greens are here to stay," she said. Even Franz, still loyal to the CDU, agrees: "The Zeitgeist is in the direction of the Greens.'' Perhaps now is the time for the party to achieve real political power.Reuse content