Go to Renault dealer and ask them,you could spend a lifetime researching it on line,two mins at the spares counter will give you the answer,if you are short of them go to a salvage yard and take some off,I'm sorry but it seems an odd request,it's not just the size but the tensile strength and how much plain section there is on the bolt and how much thread,you may find a bolt of the same SIZE but it probably wont fit,you will waste a lot of time and effort researching this one,most calipers remove quite simply with an allen key.
Rich
January 2010