$re = '/^(?:(?:\+|00)33[\s.-]{0,3}(?:\(0\)[\s.-]{0,3})?|0)[1-9](?:(?:[\s.-]?\d{2}){4}|\d{2}(?:[\s.-]?\d{3}){2})$/m';
$str = 'French Phone Number Validation.
Accept several kind of format, more or less usual. And refuse incorrect formats.
- Prefix: 0033 / +33 / (0) / 0
- Number: collapsed / group by 2 / group by 3
- Separator: space / dot / dash
~ Accepted ~
0123456789
01 23 45 67 89
01.23.45.67.89
0123 45.67.89
0033 123-456-789
0033(0)123456789
+33-1.23.45.67.89
+33 - 123 456 789
+33(0) 123 456 789
+33 (0)123 45 67 89
+33 (0)1 2345-6789
+33(0) - 123456789
~ Rejected ~
012345678
01234567890
0+123456789
(0)123456789
01 23 45 67 89
~ Accepted but strange ~
+33.-.123456789
+33.-.(0)-.-123456789
01 23.45-67.89
';
$subst = "false";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php