Abstract: A method for detecting a cleaning process in a plant having filters (1, 31) arranged spatially offset from one another, wherein a first gas (21) having solid particles (20) is conducted in a first flow direction (10) filtered by a respective filter (1, 31). To clean the respective filter (1, 31), a second gas (22) is conducted through the filter (1, 31) opposite the first flow direction (10). Then listen to noise produced in the filtering or other physical phenomena to determine a condition of the filter including if it is being cleaned. To detect a cleaning process in a plant, a respective noise (12) is detected by acoustic sensors (2, 32, 2?, 32?, 42) arranged spatially offset from one another during the cleaning of the respective filter (1, 31). Further disclosed are a system for detecting a cleaning process in a plant having such filters, and such a plant.