diff --git a/DDParsers/include/Evaluator/Evaluator.h b/DDParsers/include/Evaluator/Evaluator.h
index 86d3688d534d979f6d62f3dcf8e7abffead4359c..538c629a4c07bc320264ed8dfc285a52571f6e68 100644
--- a/DDParsers/include/Evaluator/Evaluator.h
+++ b/DDParsers/include/Evaluator/Evaluator.h
@@ -261,9 +261,9 @@ namespace dd4hep  {
       bool findFunction(const std::string& name, int npar)   const;
 
       class Object;
-      Object* object = 0;                                  // internal data
 
     private:
+      Object* object = 0;                                  // internal data
       Evaluator(const Evaluator &) = delete;               // copy constructor is not allowed
       Evaluator & operator=(const Evaluator &) = delete;   // assignment is not allowed
     };