BERLIN — At 2 a.m. on Thursday, the dance floor at Tresor in Berlin showed little indication that Germany was in the grip of a pandemic.

About 150 people were squeezed into the main space of the famous techno club, which is under a former power station. Few seemed to be heeding the “important tips for the coronavirus” that had been posted next to the stern-looking bouncers at the front door. These included “maintaining distance” in tight spaces and not “passing around drinks.”

Mercedes Sánchez, 22, was at the club celebrating the end of her medical school exams with two friends. “We know it’s maybe not such a good idea, but we thought, ‘Today and then never again,’” she said. Her group was taking “appropriate measures,” she added, like “no touching anyone, and no new friends.”

They had originally wanted to go to KitKatClub, Sánchez said, a nearby fetish and dance venue where it is not uncommon for patrons to have sex in the club. “But we thought the danger of infection there was higher,” she added.