How do you reset the brake pad wear warning light on a citroen c5?

To reset the brake pad wear warning light on a Citroën C5, first ensure that the ignition is turned off. Then, press and hold the trip reset button on the instrument panel while turning the ignition to the "On" position without starting the engine. Continue holding the button until the display shows the reset confirmation, then release it. Finally, turn off the ignition again, and the warning light should be reset.