Using terrestrial laser scanner, 344 rockfalls larger than 0.05 m<sup>3</sup> have been detected for a period of 1180 days, in a thinly bedded limestone cliff of width 750 m and height 200 m. The complementary cumulative distribution of the rockfall volume is well fitted by a power law, with an exponent <i>b</i> of 0.75 ± 0.04. In order to compare the rockfall frequencies in different geological contexts, a rockfall activity parameter has been defined, which is the number of rockfalls larger than 1 m<sup>3</sup>, which occur per century and per hm<sup>2</sup>.