Basically attached to your gearstick, are rods which translate your movements into the correct gear, if one of these gets bent then your movements aren't translated correctly, therefore you cant get into gear.
If its not your rods that are bent then frankly im clueless as im not sure on the setup of the gearbox on the Clio RS, but it maybe just an issue with your syncromesh, or it might be something more simple like something obstructing the gear.
Can't help though im afraid, take it to renault and ask for a diagnosis.