regex_match and accented characters

Hi,
I'm new member of this forum.
I use form_validation to validate a form.

I need to accept accented characters for inputs. 
To do it, I use a rule in my config array :
'rules' => array('required','regex_match[/^[\w\-\.@]{1,30}$/]' ),

However, this regexp don't accept accented characters.
As a workaround, I can add accented characters , for exemple :
'rules' => array('required','regex_match[/^[\w\-\.@àéèù]{1,30}$/]' ),

But I don't like this workaround.
How can I do ? What is the adequate regexp ?

Thanks a lot for your help