I was just walking with my guitar in a case and heard a strange noise like something is falling inside my guitar. This nut just got away from the truss rod hole (image). It seems difficult to put it back by myself, just wanted to know who I could go see to fix that (I can go to Paris, but not sure who I could contact for fixing this), if also you got this problem before. I never touched the truss rod but I guess that it went away cause it was totally relaxed (hence anticlockwise) but I am not really sure.
Thanks in advance guys for any help on this matter!