diff --git a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
index 0d051431e..90fbdb1cf 100644
--- a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
+++ b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
@@ -318,10 +318,13 @@ PyObject* SketchObjectPy::delConstraint(PyObject *args)
 PyObject* SketchObjectPy::renameConstraint(PyObject *args)
 {
     int Index;
-    char* Name;
-    if (!PyArg_ParseTuple(args, "is", &Index, &Name))
+    char* utf8Name;
+    if (!PyArg_ParseTuple(args, "iet", &Index, "utf-8", &utf8Name))
         return 0;
 
+    std::string Name = utf8Name;
+    PyMem_Free(utf8Name);
+
     if (this->getSketchObjectPtr()->Constraints.getSize() <= Index) {
         std::stringstream str;
         str << "Not able to rename a constraint with the given index: " << Index;
@@ -329,7 +332,7 @@ PyObject* SketchObjectPy::renameConstraint(PyObject *args)
         return 0;
     }
 
-    if (strcmp(Name, "") != 0) {
+    if (!Name.empty()) {
 
         if (!Sketcher::PropertyConstraintList::validConstraintName(Name)) {
             std::stringstream str;
diff --git a/src/Mod/Sketcher/Gui/CommandConstraints.cpp b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
index 39fc1d4f4..0175c311a 100644
--- a/src/Mod/Sketcher/Gui/CommandConstraints.cpp
+++ b/src/Mod/Sketcher/Gui/CommandConstraints.cpp
@@ -166,7 +166,7 @@ void openEditDatumDialog(Sketcher::SketchObject* sketch, int ConstrNbr)
                     QString constraintName = ui_ins_datum.name->text().trimmed();
                     if (Base::Tools::toStdString(constraintName) != sketch->Constraints[ConstrNbr]->Name) {
                         std::string escapedstr = Base::Tools::escapedUnicodeFromUtf8(constraintName.toUtf8().constData());
-                        Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+                        Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                                                 sketch->getNameInDocument(),
                                                 ConstrNbr, escapedstr.c_str());
                     }
@@ -2442,7 +2442,7 @@ void CmdSketcherConstrainRadius::activated(int iMsg)
                         QString constraintName = ui_Datum.name->text().trimmed();
                         if (Base::Tools::toStdString(constraintName) != Obj->Constraints[indexConstr]->Name) {
                             std::string escapedstr = Base::Tools::escapedUnicodeFromUtf8(constraintName.toUtf8().constData());
-                            Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+                            Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                                                     Obj->getNameInDocument(),
                                                     indexConstr, escapedstr.c_str());
                         }
diff --git a/src/Mod/Sketcher/Gui/EditDatumDialog.cpp b/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
index adc62d318..8b2bd2388 100644
--- a/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
+++ b/src/Mod/Sketcher/Gui/EditDatumDialog.cpp
@@ -175,7 +175,7 @@ void EditDatumDialog::exec(bool atCursor)
                     QString constraintName = ui_ins_datum.name->text().trimmed();
                     if (Base::Tools::toStdString(constraintName) != sketch->Constraints[ConstrNbr]->Name) {
                         std::string escapedstr = Base::Tools::escapedUnicodeFromUtf8(constraintName.toUtf8().constData());
-                        Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+                        Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                                                 sketch->getNameInDocument(),
                                                 ConstrNbr, escapedstr.c_str());
                     }
diff --git a/src/Mod/Sketcher/Gui/TaskSketcherConstrains.cpp b/src/Mod/Sketcher/Gui/TaskSketcherConstrains.cpp
index e8667e1ab..684071967 100644
--- a/src/Mod/Sketcher/Gui/TaskSketcherConstrains.cpp
+++ b/src/Mod/Sketcher/Gui/TaskSketcherConstrains.cpp
@@ -477,13 +477,13 @@ void ConstraintView::swapNamedOfSelectedItems()
     std::string tmpname = ss.str();
 
     Gui::Command::openCommand("Swap constraint names");
-    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                             item1->sketch->getNameInDocument(),
                             item1->ConstraintNbr, tmpname.c_str());
-    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                             item2->sketch->getNameInDocument(),
                             item2->ConstraintNbr, escapedstr1.c_str());
-    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+    Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                             item1->sketch->getNameInDocument(),
                             item1->ConstraintNbr, escapedstr2.c_str());
     Gui::Command::commitCommand();
@@ -660,7 +660,7 @@ void TaskSketcherConstrains::on_listWidgetConstraints_itemChanged(QListWidgetIte
 
         Gui::Command::openCommand("Rename sketch constraint");
         try {
-            Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, '%s')",
+            Gui::Command::doCommand(Gui::Command::Doc,"App.ActiveDocument.%s.renameConstraint(%d, u'%s')",
                                     sketch->getNameInDocument(),
                                     it->ConstraintNbr, escapedstr.c_str());
             Gui::Command::commitCommand();