An arrangement for detecting hydrogen peroxide includes a sample space configured to receive a hydrogen-peroxide-containing gas. The sample space is fluidically connected to a hydrogen-peroxide-selective colorimetric detection reagent. The arrangement also includes at least one radiation source configured to irradiate the detection reagent and at least one detector configured to detect at least one optical property of the colorimetric detection reagent. This arrangement enables detection of hydrogen peroxide in the gaseous phase without the need to transfer hydrogen peroxide to the liquid phase. As a result, a simplified measurement behavior and additionally a highly sensitive measurement are attained.