I'm guessing it's a Clio II Phase 2 on an 02 plate. If I'm right, the switch is on a panel above the stereo, along with the central locking switch. I've had the panel out enough times for other reasons, but I've never removed the switch from the panel. I can't see it being tricky though.
All you really need to do is get something thin but solid between the end of the panel and the dash, and gently lever the panel out, taking care not to mark the dash. There should be enough wire on each of the switches to allow the panel to hang down, though we had an alarm installer wire an LED into this panel on our last car and leave us with no slack at all. That made things a bit awkward.
With the panel out, unclip all connectors. This should be pretty obvious too. Then I imagine the switch will simply unclip from the rear of the panel. Again, the fixings should be obvious.
If they're not, then maybe the front has to come off the switch. It'll just be a push fit if this is the case.
I'd investigate further tonight, but I tend to need a better excuse for pulling the wife's Clio to bits