Ok, so I have the following situation,  a mysql is running:

mysql> status;
--------------
mysql  Ver 11.18 Distrib 3.23.54, for redhat-linux-gnu (i386)

Connection id:          5554
Current database:       <snip>
Current user:           <snip>
Current pager:          stdout
Using outfile:          ''
Server version:         3.23.54
Protocol version:       10
Connection:             Localhost via UNIX socket
Client characterset:    latin1
Server characterset:    latin1
UNIX socket:            /var/lib/mysql/mysql.sock
Uptime:                 3 days 17 min 41 sec


Suppose we have this table: 

mysql> describe response_text;
+-------------+------------------+------+-----+---------+-------+
| Field       | Type             | Null | Key | Default | Extra |
+-------------+------------------+------+-----+---------+-------+
| response_id | int(10) unsigned |      | PRI | 0       |       |
| question_id | int(10) unsigned |      | PRI | 0       |       |
| response    | text             | YES  |     | NULL    |       |
+-------------+------------------+------+-----+---------+-------+

And we insert a bunch of french characters:

mysql> insert into response_text (response_id,question_id,response) values
(9999,9999,"éèàâïôê");

Now we read it back:
mysql> select response from response_text where question_id=9999;
+----------+
| response |
+----------+
| éèàâïôê  |
+----------+
1 row in set (0.00 sec)

And it works prefectly, now there is also installed the following:
$ rpm -qa | grep php
php-mysql-4.2.2-17.2
php-4.2.2-17.2
$ rpm -qa | grep httpd
httpd-2.0.40-21.3

Everything is working properly except when i create a php file that contains 
the following code:
<?
        $dblink = mysql_connect(<snip><snip><snip>);
        mysql_select_db("<snip>");
        mysql_query("insert INTO response_text  
        response_id,question_id,response) "
        . "VALUES(99999,99999,\"" . $_POST['test'] . "\")");

        echo "<br>Now i'm reading it back from the database:<br>\n ";

        $res = mysql_query("select * from response_text where 
        question_id=99999");
        while($row = mysql_fetch_array($res)){
                var_dump($row);
                echo "<br>";
        }
        mysql_free_result($res);

//      mysql_query("delete from response_text where question_id=99999");

        mysql_close($dblink);
?>

Now what does this script do ? It simply puts the value in $_POST['test'] into 
the database, reads it and deletes it (i commented the delete out).
Now, when i enter the string with the accents, it goes perfectly and the output 
is:

Now i'm reading it back from the database:
array(6) { [0]=> string(5) "99999" ["response_id"]=> string(5) "99999" [1]=> 
string(5) "99999" ["question_id"]=> string(5) "99999" [2]=> string
(15) "éèàâïôê " ["response"]=> string(15) "éèàâïôê " } 

Exactly as we suspected, but notice that it isn't deleted and it is still in 
the database when i go to look into the database: 
mysql> select response from response_text where question_id=99999;
+-----------------+
| response        |
+-----------------+
| éèà âïôê  |
+-----------------+
1 row in set (0.00 sec)

It dumps this gibberish. 
A php program (phpESP) which does a query to the database and sends a mail 
containing the contents of the database also contains these gibberish 
characters (which means the conversion fails from mysql->php sometimes).

This only applies to charactes containing accents. Normal characters work fine.


I tried googling, php.net bug database and bugzilla but couldn't come up with 
an answer.
I also tried to reproduce it on my debian unstable box which failed. (debian 
box was running mysql 4.0.14, php 4.3.2)