I'm not sure if it is true in your case - just in front of the rear wheel, the side of the petrol/gas tank inlet.
It is silver, round - about 10cm long with a circumference of about 15cm - it is held in place with a black plastic clip.
Obviously, the two petrol feeder pipes is connected to it.
The fuel is under preasure at this point, so wear safety glasses when removing it.
On my car (also Renault) it is on the drivers side towards the middle of the rear door - if you place your hands under the car at that point, it is less that 10cm under the car.
Hope it helps,
zahir, June 2008
