The Germans may have given the world the Audi and the autobahn, but they have banished everything with four wheels and an engine from the streets of Vauban - a model brave new world of a community in the country's south-west, next to the borders with Switzerland and France.

    In Vauban, a suburb of the university town of Freiburg, luxuriant beds of brilliant flowers replace what would normally be parking outside its neat, middle-class homes. Instead of the roar of traffic, the residents listen to birdsong, children playing and the occasional jingle of a bicycle bell.

    "If you want to have a car here, you have to pay about Û20,000 for a space in one of our garages on the outskirts of the district," says Andreas Delleske one of the founders and now a promoter of the Vauban project, "but about 57 per cent of the residents sold a car to enjoy the privilege of living here." As a result, most residents travel by bike or use the ultra-efficient tram service that connects the suburb with the centre of Freiburg, 15 minutes away. If they want a car to go on holiday or to shift things, they hire one or join one of the town's car-sharing schemes.

    Because it has no cars, Vauban's planners have almost completely dispensed with the idea of metalled roads. Its streets and pathways are cobbled or gritted and vehicles are allowed in only for a matter of minutes to unload essential goods. Being virtually car-free is only the start of what has been hailed as one of Europe's most successful experiments in green living and one which is viewed increasingly as a blueprint for a future and perhaps essential way of living in an age of climate change.

    Vauban is a southern suburb of Freiburg and home to 5,300 people. Its elegant, weather-boarded, four-story homes are painted in subtle tones of blue, yellow and red or left as natural wood. They have wide balconies and large French windows that look out on to quiet, park-like gardens. The overall impression is of being stuck in a never-ending IKEA advertisement.

    But if the district's surface texture is eminently middle class, an eco-revolution is bubbling beneath the surface. The windows of all the homes are triple-glazed. An intricate ventilation system fitted with heat exchangers ensures that apartments are kept constantly topped-up with fresh air at room temperature, even when the windows are shut. Most homes are powered by solar panels and smart co-generator engines that run on wood chips which provide domestic heating and electricity for lighting and appliances. One of the consequences is that most of Vauban's homes generate a surplus of electricity and sell what they don't need to the power companies that run the national and regional electricity grids.

    With their 35cm thick walls, the homes are so well insulated that the temperature inside is directly affected by the number of people in each apartment. "If it gets too cold in the winter, you have the choice of turning up the heating or inviting a couple of friends round to dinner," Delleske says. He is immensely proud of the fact that his 90sqm, four-roomed "Passive house," which is almost environmentally perfect, costs a mere Û114 a year to heat. "Most people pay that kind of money for heating each month," he says. The "Passive house" has even managed to dispense with drains for the toilets and showers. The waste is reduced to compost in special biological toilets and shower and washing-up water is filtered and used to water the garden.

    Word about the Vauban experiment is spreading. Each day, six or seven busloads of visitors roll up - parking on the outskirts, needless to say - to witness the suburb's environmentally friendly living. At the entrance, they are greeted by slogan in big letters that reads: "We are creating the world we want."

    Yet the suburb's origins were very remote from such idealistic themes. It started life in 1937 as the Leo Schlageter army barracks, a collection of three-story stone buildings to house Adolf Hitler's expanding Wehrmacht army. It was named after a German hero from the First World War who was executed by the French in 1923. At the end of the Second World War, the barracks were requisitioned by the French army and renamed Quartier Vauban, after a noted 17th century military architect. After Germany's re-unification, the French withdrew and the district was handed over to the city of Freiburg in 1994, to be promptly occupied by squatters.

    Soon after, a group of ecologically minded and mostly middle-class people became interested in the quarter. Many had taken part in the anti-nuclear movement as students in the 1970s and 1980s. They set up the Forum Vauban, which began negotiating with the city government.

    Vauban's founders explain that much of the eco-friendly technology that has gone into the complex was conceived and developed around Freiburg as an alternative to nuclear power. The upshot was the formation of a series of loosely structured housing associations which commissioned architects to design new and ecologically sustainable homes on the site. Most of the old Nazi-era barrack buildings were torn down and more than 60 architects were engaged to reconstruct Vauban. Its three- to five-story buildings contain apartments of varying sizes and 80 per cent are privately owned. A four-bedroom unit costs about Û250,000.

    The project is a reminder of the strength of Germany's green movement. Freiburg's city government is run by a coalition of conservatives and Green Party councillors and the Greens hold the most seats. During the European elections, the Green Party won up to 60 per cent of the poll in Vauban's constituencies.

    The district also bucks Germany's reputation for having one of the world's lowest birth rates: nearly 30 per cent of its inhabitants are aged under 18. Ute and Frank Lits moved to Vauban five years ago. Their children, aged six and 10, can walk out the front door of their four-bedroom apartment into a communal garden equipped with a playground and a wood-fired pizza oven. "We wanted to buy our own home and we liked the eco-friendly principles of the place," Mrs Lits said. "But the main reason is that Vauban is perfect for children. They enjoy the kind of freedom that it would be difficult to find in a normal town apartment." The couple owns a car, but neither mind having to park it in a communal garage eight minutes' walk from their home.

    If Vauban's brave new world suffers from anything, it is its own peculiar brand of middle-class monoculturalism. Sitting outside a former Nazi barrack building that now functions as an organic restaurant selling ricotta-filled ravioli and ostrich meat, its is difficult to spot anyone who is non-European, old or poor.

    Wolfgang Konradi, a youth worker who spent years working in less-sophisticated urban areas before coming to Vauban, says the district's teenagers behave like normal people of their age. "The problem is mainly the parents, they go around expecting their offspring to be perfect citizens, but that's just not realistic," he laments. Ina, his wife, said that since having their son, she had learned to appreciate the advantages that Vauban offered for children. But she added: "It's very nice here, but a bit like living under a bell jar. I certainly wouldn't want to live here forever."