Whats up with my peugeot 206??

Hi, don't know if any1 can help me but i have a 03 206. All the time now when i unlock my car and when i switch the engine on/off there is a sort of 'clicking' noise that seems to be coming from just above the CD player, it happens even if there is no CD in. It is really annoying and can be quite embarrasing, im just hoping its someting easy to sort out. Any info that will help me sort it would be greatly apprciated