A capacitive sensor for a vehicle seat comprises an antenna electrode and a control and evaluation circuit operatively connected to the antenna electrode. The control and evaluation circuit is configured to operate in a first mode of operation, during which it measures alternating electrical current flowing between the antenna electrode and ground. The capacitive sensor comprises a seat frame connector for connecting the control and evaluation circuit to the seat frame of the vehicle seat. The control and evaluation circuit is configured to operate in a second mode of operation, during which it measures electrical current flowing into the seat frame connector.