Seems like a common enough failure.

You're motoring along in your Megane II, go to select a different gear by depressing the clutch pedal, and the movement is accompanied by a loud 'twang' as the clutch pedal return spring separates itself into 2 pieces.

I'm surprised that info on this failure seems sparse, but occurrences seem numerous enough.

The failure is not accompanied by any real degradation in clutch function unless the broken spring snags the back of the clutch pedal when it fails and stops the clutch pedal returning to rest fully. Then you'll get all sorts of fun with the clutch slipping until the spring is extricated from it's little cubby in the top of the clutch pedal box.

Seems as though Renault don't want you replacing just the spring though as they don't sell a separate replacement - they insist you buy the whole clutch pedal box assembly for $650 !!! (This sales technique seems to be a common thread with recent Renaults - just try buying a steering rack bush or power window controller separately ! ). Luckily the enterprising aftermarket guys are on top of these sorts of supply issues.

Renault offered to supply a spring out of a Traffic (?) for $176 but I declined

I measured the spring as follows :
O.D - 20mm
I.D - 12.9mm (but the base of the plastic carrier is actually 12mm
Free Length - 50mm
Solid Length - 30mm
Wire Diameter - 3.5mm

I jumped online and found Century Springs in Sandgate (Newcastle NSW) had a pretty good range.

Century Springs Pty. Ltd. - Product Catalogue


I bought a #3139 spring for $18 (ended up being $32 delivered) but it is a little short and needed a 12mm washer underneath it when installed to achieve the correct length.

A #10052 spring might have been a better choice as it has a little more free length.