In Berlin, more than 500,000 of the 3.5 million inhabitants get on their bikes daily to move about the city, twice as many as a decade ago, making the most of an extensive network of cycle paths.

On Unter den Linden, the capital's celebrated, tree-lined central boulevard, cyclists zoom up and down between the pedestrians and hordes of tourists admiring the Brandenburg Gate.

'Beer bikes' pedalled simultaneously by about a dozen or so people who drink beer while cycling around the city are also a common sight in the German capital.

"There is a real problem with the cyclists who do not respect the rules, who zigzag and ride any old way. They are becoming less and less civilised," Tahmaures, a 58-year-old taxi driver, fumed.

Germany traditionally conjures up images of a nation of car lovers, but the Transport Ministry said there had been "a renaissance of the bicycle since the beginning of the 90s".

And it is concerned about the high number of accidents suffered by cyclists.

One in three accidents in towns involved bicycles last year, and the rate was one in four for fatal accidents, according to the German Statistics Institute.

"Infrastructure for traffic is no longer suitable. The growing number of cyclists requires a new concept for urban organisation," Claudia Nolte, spokeswoman for the German Automobile Club for the Berlin-Brandenburg region, said.

In 2011, the German federal state devoted EUR 86 million (USD 118 million) to cycling infrastructure.

Critics, however, complain that cyclists tend to run red traffic lights, cycle the wrong way up one-way streets and take up too much of the pavement without regard for pedestrians.

"Aggressiveness is not solely the domain of bikes, there is also a lot of rudeness by drivers who do not pay attention to bikes," Roland Huhn, of the German cyclists' association, said for his part.

In a book published earlier in the year, author Annette Zoch criticised cyclists for hiding behind the excuse that their chosen mode of transport is environmentally-friendly.

"On a bicycle, man becomes a monster," Zoch said in her ironically written "Book for those who hate bikes", while the respected Der Spiegel weekly has devoted its front page to conflicts caused by the rise of the bike.

In Freiburg, the south-western German city which prides itself for its strong ecological achievements, a third of all movement around the city is done by bicycle which authorities have promoted since the 1970s.

A giant car park near the train station can even host 1,000 bicycles.

Some of the city centre's narrow streets, though, have become so blocked by bikes, pedestrians can hardly get through and a ban on the parking of bicycles has been imposed in some places.

"Relations between pedestrians and cyclists have rather deteriorated," said Stefan Lieb, spokesman of the pedestrians' association Fuss e.V., adding it was mainly because bike use had grown so much.

Some German towns and cities, including Berlin and Munich, have imposed speed limits of 30 kilometres an hour (18.6 miles an hour) in certain areas or turned over certain streets for sole bike use.

AFP/ Benoit Toussaint/Expatica