The poelple there can't be so stupid to not figure out

"Poelple"

Wow. A lot of people must have fallen for someone to post that on each step.

Has anyone ever heard of a thing called "humor"? ZIS IS A SHOKE ! BETRACHTEN SIE MEINEN SCHNURRBART!

Well, the "Vorsicht Stufe"-stickers in the entrance hall of the Humboldt University Berlin have been installed by internationally acclaimed conceptual artist Ceal Floyer from London and are meant as modern art, see e.g. Google search for "Ceal Floyer Vorsicht Stufe".