IMPORTANT: when converting UTF8 data that contains the EURO sign DON'T USE utf_decode function.

utf_decode converts the data into ISO-8859-1 charset. But ISO-8859-1 charset does not contain the EURO sign, therefor the EURO sign will be converted into a question mark character '?'

In order to convert properly UTF8 data with EURO sign you must use:

iconv("UTF-8", "CP1252", $data)

Source: http://php.net/manual/fr/function.utf8-decode.php