You can apply a degreaser with some elbow grease to remove the coating - it is what's known as a 'soft touch' coating to make the plastic not feel grainy and harsh to the touch.

By removing this the handles won't be nice to the touch. You may be able to rub back the plastic with wet and dry sandpaper and reapply plastic primer, but it might just be easier and cheaper to source new handles either from a breakers or from Renault itself.