I think i've found something :
DateFormat df = new SimpleDateFormat( "MMM-dd-yyyy-HH:mm", Locale.FRENCH );
System.out.println( df.format( Calendar.getInstance().getTime() ) );
Result : juillet-25-2006-10:17
DateFormat df = new SimpleDateFormat( "MMMM-dd-yyyy-HH:mm", Locale.FRENCH );
System.out.println( df.format( Calendar.getInstance().getTime() ) );
Result : juil.-25-2006-10:17
So the format given by the FTP server doesn't match what is expected.
Changing "juil-7-2006-10:16" to "juil.-7-2006-10:16" will parse but i still don't know how to solve the problem.