An access system for a building, wherein several key compartments are publically accessible in at least one area of the building, wherein one key compartment from among the several key compartments exhibits at least one key for at least one building door (2, 2') of the building, and wherein this key is accessible by removing at least one lock of the key compartment, wherein the access system exhibits the following: the at least one building door (2, 2'), which exhibits at least one transceiver (21, 21'), wherein the at least one transceiver (21, 21') is set up to receive an identification code of the key stored by the key if the key gets within at least one coverage range of the transceiver (21,21'); at least one testing device (22, 22') set up to check whether at least one valid access authorization for the building door (2, 2') exists for the received identification code; at least one locking device (23, 23') in a door decoration, which is set up to unlock the building door (2, 2') if a valid access authorization for the building door (2, 2') does exist for the received identification code; and at least one emergency sensor (6, 6', 6", 6"') in at least one area of the building, wherein this emergency sensor is set up to acquire at least one signal and communicate at least one signal and/or emergency signal to at least one center, wherein the center communicates an activation signal to the key compartment for a communicated emergency signal; characterized by a sabotage sensor exhibited by the key compartment, wherein this sabotage sensor is set up to acquire a removal of the lock, and to generate at least one sabotage signal for an acquired removal of the lock, which is set up to transmit the sabotage signal to a communication device of the key compartment via at least one signal line, wherein this communication device is set up to communicate the sabotage signal to the center via a local radio network, wherein this center is set up to receive the sabotage signal via an antenna of the center, wherein at least one controller of the center is set up to compare whether an emergency is present for the received sabotage signal of the key compartment, wherein an emergency is present if the controller has previously sent an activation signal to the key compartment, and a closing device of the key compartment has opened the lock for this activation signal, wherein no emergency service is alerted if an emergency is present, wherein, if no emergency is present, the controller is set up to alert at least one emergency service for a received sabotage signal, and that at least one alert to the emergency service contains at least one indication as to the location and/or time of day of a sabotage to the key compartment correlated with the sabotage signal. the at least one building door (2, 2'), which exhibits at least one transceiver (21, 21'), wherein the at least one transceiver (21, 21') is set up to receive an identification code of the key stored by the key if the key gets within at least one coverage range of the transceiver (21,21'); at least one testing device (22, 22') set up to check whether at least one valid access authorization for the building door (2, 2') exists for the received identification code; at least one locking device (23, 23') in a door decoration, which is set up to unlock the building door (2, 2') if a valid access authorization for the building door (2, 2') does exist for the received identification code; and at least one emergency sensor (6, 6', 6", 6"') in at least one area of the building, wherein this emergency sensor is set up to acquire at least one signal and communicate at least one signal and/or emergency signal to at least one center, wherein the center communicates an activation signal to the key compartment for a communicated emergency signal; a sabotage sensor exhibited by the key compartment, wherein this sabotage sensor is set up to acquire a removal of the lock, and to generate at least one sabotage signal for an acquired removal of the lock, which is set up to transmit the sabotage signal to a communication device of the key compartment via at least one signal line, wherein this communication device is set up to communicate the sabotage signal to the center via a local radio network, wherein this center is set up to receive the sabotage signal via an antenna of the center, wherein at least one controller of the center is set up to compare whether an emergency is present for the received sabotage signal of the key compartment, wherein an emergency is present if the controller has previously sent an activation signal to the key compartment, and a closing device of the key compartment has opened the lock for this activation signal, wherein no emergency service is alerted if an emergency is present, wherein, if no emergency is present, the controller is set up to alert at least one emergency service for a received sabotage signal, and that at least one alert to the emergency service contains at least one indication as to the location and/or time of day of a sabotage to the key compartment correlated with the sabotage signal.