BERLIN — In Germany, women are paid an average of 21 percent less than men, one of Europe’s widest gender pay gaps. In Berlin next week, for one day only, the public transportation system will offer them a corresponding discount.

The BVG, which runs the city’s bus, tram and subway systems and is the country’s largest public transit authority, will offer women an unlimited day pass for 5.50 euros, about $6.20, instead of the regular €7.

The Frauenticket, or women’s ticket, is limited to Monday, which campaigners in Germany have designated as Equal Pay Day, and the authority is calling the promotion “Mind the Pay Gap.”

“The women’s ticket not only challenges the discriminatory wage gap in our country, but also shows that the BVG itself is doing something about it,” Sigrid Nikutta, the authority’s director, said.