Hmmm, me too - I have a 1998 1.2 Clio and the button works on the centre console, but locking/unlocking either of the front doors does not operate the central locking.
some facts ... The key has a battery - I changed it but still no good. (Although I think the battery just feeds the LED bulb in the key). i.e. I don't think the key is a remote sender for the locking - however locking the front doors should operate the locking
I know the previous owner very well and she's advised that it's never worked and that Renault wanted £200+ to fix it.
Any appropriate help gratefully accepted :)
Dave D
December 2008