Abstract: A snooper device that can be used to memorize data elements relating to the most recent instances of parking, notably for proof in the event of disputes, in time-accounting devices, and notably time-accounting devices for reckoning periods of parking regulated by rules. This snooper device comprises first means to memorize operation checking data elements in which there are written, at each fresh use of the time-accounting system, data elements corresponding to the time and to the date of commencement of at least each instance of parking and data elements corresponding to the time and to the date of the end of this instance of parking.