The Mégane II Owners' Club

I too have this problem with the parcel shelf. Mine has been like it since i got the car brand new. I had it checked by Renault while it was under warranty and they informed me that the parcel shelf was in fact warped but they would not replace it under warranty for some reason!
Mine too is okay if i leave the support strings unattached, buit if attached as soon as i close the boot you hear the shelf pop out of place. It then causes an annoying noise if you go over bumps etc as it moves around!

Wifes used to do the same,it was catching on the back of the seat as you closed the boot causing it to pop off the locating spigot on nearside I got round it by removing the boot light housing which has the nearside lid locating spigot (couple of star bit bolts) when removing need a small tug but take care not to damage the wiring for the light as its attached, you can then refit a little bit further back, you will see the plastic that the screw locates into is an elongated hole giving you some room to play with, it was alittle bit of trail and error as to far back causes shelf to deform against the bulge in the boot lid for the wiper arm. obviously if its popping off the opposite side do procedure on that one.

Thinking about it one way to test if its catching the back seat that is doing it is to drop your rear seats and see if shelf stays where it is when you close boot.

In case it helps, I measured my strings over the weekend. 265mm / 10½" centre-to-centre. I have had this problem once or twice after removing and replacing the shelf - due to the "hinges" not snapping back into position fully. It can be a bit tricky to fit correctly, especially if you're in a hurry.