The cause of the collapse is under investigation, but police suspect that a gas explosion caused the 19th-century building to collapse.
The rescue operation was underway on Tuesday as a precaution, using gas meters.
According to police, the building contains rental accommodation for tourists and vacationers. Initially, five people were missing, but two of them had not yet arrived at their rented accommodation.
"They were lucky they weren't there," police spokeswoman Anja Leuschner told DW.
