COPP :

The COPP system manages the opening and closing of the platform screen doors installed at the Porte de Châtillon station independently from the train’s automatic driving mechanisms… COPP, thanks to sensors, observes a portion of the track area and analyzes the behaviour of trains travelling through stations.

When a train has come to a stop and is in its proper position, the COPP system then commands the platform doors to open or close.