The invention relates to a system including a lock (10) provided with electronic NFC transceiver circuits and electric circuits for controlling mechanical locking/unlocking members, and a portable telephone (16) provided with circuits for NFC mode of operation. The telephone comprises means for initializing the lock, said means including means for: downloading, from a remote site (20), an applet and elements required for initializing the lock; verifying, using the telephone, the identifier and the transport key stored in the lock against the downloaded ones; deactivating the transport key of the lock; loading, onto the lock, a unique random algorithm and a cryptographic key that have been downloaded; and generating a message notifying of the termination of the initialization of the lock.