diff --git a/app/models/contact.rb b/app/models/contact.rb
index 5bfc1ae00..01a4bab3d 100644
--- a/app/models/contact.rb
+++ b/app/models/contact.rb
@@ -29,7 +29,7 @@ class Contact < ApplicationRecord
   }
 
   NAME_REGEXP = /([\u00A1-\u00B3\u00B5-\u00BF\u0021-\u0026\u0028-\u002C\u003A-\u0040]|
-    [\u005B-\u005F\u007B-\u007E\u2040-\u206F\u20A0-\u20BF\u2100-\u218F])/x
+    [\u005B-\u005F\u007B-\u007E\u2040-\u206F\u20A0-\u20BF\u2100-\u218F])/x.freeze
 
   validates :name, :email, presence: true
   validates :name, format: { without: NAME_REGEXP, message: :invalid }