The driver's door has the most use and the most wear. The wiring connecting the driver door electrics to the main body flexes many times more than the other doors and the resulting problems usually occur first to this door.

It is not unusual for the harness to develop some internal breaks where most flexing takes place, though Peugeot seem particularly vulnerable to problems with the plug and socket making reliable contact after much use where plug-in doors are used.

If your doors are the plug-in type I suggest you check there first to ensure reliable contact.