You have a pretty long string that appears exactly the same in each of your examples: serveurdhcpANNUAIREITEMSACCESSOIRES ACAPOIGNÉESPOIGNÉES STANDARD ACA (COLLECTION MODERNE & CLASSIQUE)
Is it always the same for all records you are sorting?
If so, try setting up a caculation field that just extracts the last portion of this field, ( Collection Classique in the first example records after sorting ) and just sort on this one field.
thanks a lot for your post, it made me understand the problem.
my field doesn't always have the same beginning since this is a physical path to pdf files.
But filemaker didn't sort it correctly because it only sort the first 100 characters of a string.
I will use another field that i have and i will acheive my goal :)
thaniks a lot !!!