Mine has nothing like that in my fuse box, don't know what its for though. Thats a pretty tight squeeze to get anything in there which suggests someone brought it down for a reason.
Might help to give a picture of the end of the connector to see the shape, though I had most of the dash off mine at one point and can't remember seeing a connector like that. The black/white loops back into itself? very odd :\
What about the dummy switch to the left of the steering wheel, have Renault put the loom in just incase? If everything is working fine wouldn't worry about it
Edit: defo that dummy plug had a look past the steering wheel cowl and can see it plugged in to there with the same coloured wires. What's that "switch" for, parking sensors?