Regular expression

Question

I am  having a text box which must allow only the below special characters from user side of entry.

-  \  /  ~  * .  ?   %   ( )  [ ] { } = + &   # £ $ ; : @ ^ _ + ¬¬ – è é


I am not not sure whether we can put validation for  these 2 characters è é .


Happy to get any help from your side.