diff --git a/src/App/DocumentPyImp.cpp b/src/App/DocumentPyImp.cpp
index 2f0d15cf0..ef72547df 100644
--- a/src/App/DocumentPyImp.cpp
+++ b/src/App/DocumentPyImp.cpp
@@ -319,10 +319,18 @@ PyObject*  DocumentPy::moveObject(PyObject *args)
 
 PyObject*  DocumentPy::openTransaction(PyObject *args)
 {
+    PyObject *value;
+    if (!PyArg_ParseTuple(args, "|O",&value))
+        return NULL;    // NULL triggers exception
     char *pstr=0;
-    if (!PyArg_ParseTuple(args, "|s", &pstr))     // convert args: Python->C 
-        return NULL;                             // NULL triggers exception 
-
+    if (PyUnicode_Check(value)) {
+        PyObject* unicode = PyUnicode_AsLatin1String(value);
+        pstr = PyString_AsString(unicode);
+        Py_DECREF(unicode);
+    }
+    else if (PyString_Check(value)) {
+        pstr = PyString_AsString(value);
+    }
     getDocumentPtr()->openTransaction(pstr); 
     Py_Return; 
 }