In a method and system and franking apparatus for franking postal matter and for inspection of the franking, postage fees are stored and debited in electronic form, and a fee stamp and a machine-readable date stamp containing encrypted data are applied to the postal matter. In order to satisfy high security demands to be met at a low cost, and to allow realization on a standard computer with a printer without additional hardware, an individual date stamp, distinguishable from the date stamps generated for other pieces of mail is generated for each piece of mail and is applied to the piece of mail. An inspection for multiple employment of postage fees and/or date stamps ensues on the basis of the date stamp. This inspection includes comparing a date stamp to be inspected to previously used date stamps stored in a data bank. Defrauders thus can be identified who, without paying, attempt to generate frankings or to multiply employ frankings, for example by copying.