diff --git a/common/configparser.cc b/common/configparser.cc
index c1e387fcc5abe538abb6fb245f90287f44afac87..95746777cf0fed7efadbae8c3e1a2b59e16dfb43 100644
--- a/common/configparser.cc
+++ b/common/configparser.cc
@@ -182,7 +182,7 @@ string& ConfigParser::operator[] (const string& key)
   }
 }
 
-string ConfigParser::get(const string& key, string defaultValue)
+string ConfigParser::get(const string& key, const string& defaultValue)
 {
   if (hasKey(key))
     return (*this)[key];
diff --git a/common/configparser.hh b/common/configparser.hh
index 8a3359cad88dea9756c504e6e43cff21c528eec6..2b345184277673dcd1db4aa53aebddc9e306e510 100644
--- a/common/configparser.hh
+++ b/common/configparser.hh
@@ -145,7 +145,7 @@ namespace Dune {
      * \param defaultValue default if key does not exist
      * \return value as string
      */
-    std::string get(const std::string& key, std::string defaultValue);
+    std::string get(const std::string& key, const std::string& defaultValue);
 
 
     /** \brief get value as int