diff --git a/src/blockforest/python/Exports.cpp b/src/blockforest/python/Exports.cpp
index 17f1b253409fee193e0d26cad6d722dd759ac549..83ef6f6628cc303d9ae41ebd0dbc38aa1a7f9b34 100644
--- a/src/blockforest/python/Exports.cpp
+++ b/src/blockforest/python/Exports.cpp
@@ -126,7 +126,7 @@ object python_createUniformBlockGrid(tuple args, dict kw)
    shared_ptr<Config> cfg = python_coupling::configFromPythonDict( kw );
 
    try {
-      shared_ptr< StructuredBlockForest > blocks = createUniformBlockGridFromConfig( cfg->getGlobalBlock(), NULL, keepGlobalBlockInformation );
+      shared_ptr< StructuredBlockForest > blocks = createUniformBlockGridFromConfig( cfg->getGlobalBlock(), nullptr, keepGlobalBlockInformation );
       return object(blocks);
    }
    catch( std::exception & e)
diff --git a/src/python_coupling/Manager.cpp b/src/python_coupling/Manager.cpp
index 9ccf4a597e06b5a80f0346702484112ecdbd41f1..82bf23cf29fc0cb1dbdbb14985d264ed639cd0c6 100644
--- a/src/python_coupling/Manager.cpp
+++ b/src/python_coupling/Manager.cpp
@@ -114,7 +114,7 @@ void Manager::triggerInitialization()
 
    }
    catch ( boost::python::error_already_set & ) {
-      PyObject *type_ptr = NULL, *value_ptr = NULL, *traceback_ptr = NULL;
+      PyObject *type_ptr = nullptr, *value_ptr = nullptr, *traceback_ptr = nullptr;
       PyErr_Fetch(&type_ptr, &value_ptr, &traceback_ptr);
 
       if( type_ptr )
diff --git a/src/python_coupling/Shell.cpp b/src/python_coupling/Shell.cpp
index 85cb228121ae7814b0afadee4a7f386a9de7df1e..183e329d3d6c13b748c61e52ccbb19e7ef359e25 100644
--- a/src/python_coupling/Shell.cpp
+++ b/src/python_coupling/Shell.cpp
@@ -116,7 +116,7 @@ namespace python_coupling {
          else
             line = PyOS_Readline( stdin, stdout, (char*)prompt2_.c_str() );
 
-         if ( line == NULL || *line == '\0' ) {  // interrupt or EOF
+         if ( line == nullptr || *line == '\0' ) {  // interrupt or EOF
             result.clear();
             return false;
          }
diff --git a/src/python_coupling/basic_exports/BasicExports.cpp b/src/python_coupling/basic_exports/BasicExports.cpp
index d43a339f956486c8aec218208ca771836e2715d6..17341f26bdb5d83badef0e42ad26a63b037fdbc1 100644
--- a/src/python_coupling/basic_exports/BasicExports.cpp
+++ b/src/python_coupling/basic_exports/BasicExports.cpp
@@ -67,7 +67,7 @@ struct NumpyIntConversion
        auto typeName = std::string( Py_TYPE(pyObj)->tp_name );
        if ( typeName.substr(0,9) == "numpy.int" )
           return pyObj;
-       return 0;
+       return nullptr;
     }
 
     static void construct( PyObject* pyObj, converter::rvalue_from_python_stage1_data* data )
@@ -94,7 +94,7 @@ struct NumpyFloatConversion
        auto typeName = std::string( Py_TYPE(pyObj)->tp_name );
        if ( typeName.substr(0,11) == "numpy.float" )
           return pyObj;
-        return 0;
+        return nullptr;
     }
 
     static void construct(PyObject* pyObj, converter::rvalue_from_python_stage1_data* data)
@@ -208,7 +208,7 @@ struct PythonTuple_to_Vector3
       using namespace boost::python;
 
       if ( ! ( PySequence_Check(obj) && PySequence_Size( obj ) == 3 ))
-         return NULL;
+         return nullptr;
 
       object element0 ( handle<>( borrowed( PySequence_GetItem(obj,0) )));
       object element1 ( handle<>( borrowed( PySequence_GetItem(obj,1) )));
@@ -219,7 +219,7 @@ struct PythonTuple_to_Vector3
             extract<T>( element2 ).check() )
          return obj;
       else
-         return NULL;
+         return nullptr;
    }
 
    static void construct( PyObject* obj, boost::python::converter::rvalue_from_python_stage1_data* data )
@@ -302,7 +302,7 @@ struct PythonTuple_to_Cell
       using namespace boost::python;
 
       if ( ! ( PySequence_Check(obj) && PySequence_Size( obj ) == 3 ))
-         return NULL;
+         return nullptr;
 
       object element0 ( handle<>( borrowed( PySequence_GetItem(obj,0) )));
       object element1 ( handle<>( borrowed( PySequence_GetItem(obj,1) )));
@@ -313,7 +313,7 @@ struct PythonTuple_to_Cell
             extract<cell_idx_t>( element2 ).check() )
          return obj;
       else
-         return NULL;
+         return nullptr;
    }
 
    static void construct( PyObject* obj, boost::python::converter::rvalue_from_python_stage1_data* data )