Six pillars of the monument at the heart of the German capital were sprayed with orange warning paint, the group said in a statement.
The paint spread to the Pariser Platz, the square at the foot of the monument, with bright footprints extending along the roadway.
Fourteen people were arrested at the site, police told AFP, without any indication of acts of violence.
The demonstrators wanted to send the message that it is "time for political change" in order to "move away from fossil fuels", according to the statement.
"We must get out of petrol, gas and coal no later than 2030. It is high time that (German Chancellor) Olaf Scholz speaks clearly," Last Generation spokesperson Marion Fabian said in the statement.
Germany wants to reach net zero targets by 2045.
© 2023 AFP
