Women's groups across Germany are preparing protests on Friday to highlight the yawning pay gap between the sexes, one of the worst in Europe.
The date, March 20, has not been chosen by chance.
According to the protest organisers, this is the date up to which German women on average had to work this year, on top of last year's salary, to earn as much as their male counterparts did in 2008.
On average, women in Germany earn nearly a quarter less than men, compared to an average of 17 percent in the rest of Europe, with several factors specific to Germany making it hard for women to bridge the gap.
"The tax system in Germany encourages women to take a part-time job when their husband earns more than them," Astrid Ziegler, a researcher at the WSI in Duesseldorf, told AFP.
In addition, a scarcity of places at German creches, as well as the fact that schools are not open all day, makes it difficult to combine a job with family life, she added.
The situation is very different on the two sides of the former Berlin Wall.
The latest official statistics, from 2006, showed a salary gap of 25 percent in the former West Germany, compared to only six percent in the former communist East Germany (GDR).
Until the country reunified in 1990, "all the women in the former GDR worked, there was a system of creches and it was considered normal that they earned the same amount as men," Dagmar Bischof, president of the Business and Professional Women (BPW) network said.
When the Berlin Wall fell, however, "it was unfortunately not the East German system that was adopted in the west, but the reverse," she added.
In addition, women who choose to work in Germany rather than tend to their children are often seen as bad mothers, she said.
"The mentality has to change."
Although the government, disturbed by the country's extremely low birth rate, has tried to improve conditions for working mums, Ziegler said: "The politicians could do more. And there is no global strategy."
There is "segregation on the job market," she added, with over a third of women working part-time.
Only two women serve on the management boards of Germany's top 30 listed companies, and female executives are less well paid than the men in the boardroom, she said.
This makes the "Equal Pay Day" protests all the more important, she said. "It draws attention to the problem."
More than 180 separate events were planned across Germany Friday and the initiative is supported by the families minister, the main employers' federation and women's groups.
Austria, Belgium and Switzerland have also adopted the idea, first conceived in the US in the 1990s, and Poland, France and Italy are set to follow suit, Bischof said.