A door arrangement (1), includes a safety device. A door arrangement monitoring method monitors a monitored area positioned in front of a door opening, offset and parallel to a door closing plane, and performs a failure routine when an object (6) is detected in the monitored area and there is a risk of a collision of the object (6) with a door leaf (2). A current position of the object (6), and of a leading edge (23) of the door leaf (2), are detected. A direction of movement of the door leaf (2) is detected. The failure routine is initiated as a function of the current position of the object (6) and the leading edge (23) of the door leaf (2) as well as the direction of movement of the door leaf (2).