Thank you for your reply. 

You were right, it was weird and Forrest wasn't guilty. 

The file I meant was index.xml, as you guessed. And the encoding tag was written
in this file.

After I had posted to gmane, I tried to write é instead of é : it worked
well. But it's so bothering to write HTML special characters... 

When I got my problem, I was working with Textpad because of slow PC problem... 
But yesterday I worked with Oxygen and é, à are handled very well by Forrest. 
It seems that Textpad is doing some naughty thing in my xml. 

To sum up : there is not a single problem with Forrest, there is a problem with
my text editor. 

Bye
Jérôme