-> Open GIMP 2.6 and create a new image.
-> Create two new layers named "é" and "e".
-> Open the script-fu console.
-> Get the ID of each layer.
     (to get the ID of a layer:
	-get the ID (imageID) of the image by seeing the top of its window
         (imageName-imageID)
	-in the layer dialog select the layer that you want to now its ID
	-type this on the console : (gimp-image-get-active-drawable imageID) ,
         it returns the active layer ID
     )

-> type this:
	> (car (gimp-drawable-get-name lay1))
  	==> "é"
	> (car (gimp-drawable-get-name lay2))
	==> "e"
   for the moment : no error	
   (> means what you type, ==> means what GIMP returns, lay1 is the ID of the 
   layer named "é" and lay2 is the ID of the layer named "e")

-> type this:
	> (string-append "é" "a")
	==> "éa"
	> (string-append "e" "a")
	==> "ea"
   no error

-> type this:
	> (string-append (car (gimp-drawable-get-name lay1)) "a")
	==>
	> (string-append (car (gimp-drawable-get-name lay2)) "a")
	==> "ea"
   The second expression does not create an error.
   The first expression must returns "éa" but GIMP does not return anything.

-> type this :
	> (string-append (car (gimp-drawable-get-name lay1)) "é")
	==>
	> (string-append (car (gimp-drawable-get-name lay2)) "é")
	==> "eé"
   Note that the behaviour of GIMP is the same if you type "a" or any other
   character or string in the string-append expression.

-> type this
	> (gimp-drawable-set-name lay1 
            (string-append (car (gimp-drawable-get-name lay1)) "a") )
	==> Error: Procedure execution of gimp-drawable-set-name failed on 
            invalid input arguments: La procédure « gimp-drawable-set-name » a 
            été appelée avec la valeur «  
	> (gimp-drawable-set-name lay2
            (string-append (car (gimp-drawable-get-name lay2)) "a") )
	==> (#t)
   The first expression returns an error, it is logic because the string-append 
   expression does not return anything.

-> Now change the name of the layer named "é" by "²", "è", "à", "°","§", "ù",
   "§", "ù", "ô", "ï" or what you want.
   Note that if the name of the layer contains certain characters and if you 
   type this : (string-append (car (gimp-drawable-get-name lay1)) "a") ,  it 
   generates an error.