Regular expression

   string text = "résumé";  

   string regExp = @"^[a-zA-Z0-9\\/~*.?%()[\]{}=+&#£$;:@^_+¬¬–èé-]+$";

   Console.WriteLine(Regex.IsMatch(text, regExp));

it returned True.

However, if I placed an accute accent over the 'u':

   string text = "résúmé"; 

it returned False.

Note, though, that you'll need to use a-zA-Z0-9_ instead of \w. The latter seems to match all word characters (whether unaccented English letters or not) which is not what you want here.