You create the following:
You throw a string in each:
You compile the application and it defaults to english and comes up fine
You change the compiler arguments in project properties to -locale fr_FR and run it and instead of an è you get either a blank or a square
Solution: The text encoding type of the Flexapp.properties file in flexbuilder defaults to ISO-8859-I. Cut out all the text in the file, save it. Go to the properites of the file and change the encoding to UTF-8. Then paste your text back in and save. Now when you compile and run the letters should come up fine.