Demonstrators in cities including Berlin, Hamburg and Bonn called on Chancellor Olaf Scholz's government to exit oil, coal and gas and end fossil fuel investments.

Some held up signs that read "Save Our Future" and "Earth First".

Overall, more than 75,000 people rallied in around 110 towns and cities across the country, Fridays for Future said.

Mass protests are "the most important way to achieve change", Carla Reemtsma, a spokeswoman for Fridays for Future Germany, told Bavarian broadcaster Bayerischer Rundfunk.

But a similar nationwide protest day five years ago attracted a far bigger crowd of 1.4 million people.

The Fridays for Future movement started in 2018 when Swedish activist Greta Thunberg began sitting outside Sweden's parliament every Friday to demand more climate protection efforts.

The movement quickly snowballed into global youth climate strikes and marches that attracted millions of people.

However, the movement was less visible during the pandemic and it has struggled to regain momentum in recent times.

Friday's protests came after Storm Boris brought torrential rain and widespread flooding to parts of central and eastern Europe this month, causing devastation and leaving 24 people dead.

Sebastian Bock, a demonstrator in Berlin, said the floods were a reminder that the catastrophic effects of climate change were already being felt.

"With the bad floods that we have seen, you have to draw the connection that they are simply more frequent due to climate change," he told AFP.

Experts say climate change caused by human-generated greenhouse gas emissions is increasing the frequency and intensity of extreme weather events, such as torrential rains and floods.