How to convert ISO8859-15 to UTF8?

I found this to work for me:

iconv -f ISO-8859-14 Agreement.txt -t UTF-8 -o agreement.txt

Could it be that your file is not ISO-8859-15 encoded? You should be able to check with the file command:

file YourFile.txt

Also, you can use iconv without providing the encoding of the original file:

iconv -t UTF-8 YourFile.txt