diff --git a/pytec/tec_qt.py b/pytec/tec_qt.py
index e96b928..4075a0c 100644
--- a/pytec/tec_qt.py
+++ b/pytec/tec_qt.py
@@ -73,7 +73,7 @@ class MainWindow(QtWidgets.QMainWindow):
         self.autotuners = PIDAutoTuner(self, self.client, 2)
 
         def get_ctrl_panel_config(args):
-            with open(args.param_tree, "r") as f:
+            with open(args.param_tree, "r", encoding="utf-8") as f:
                 return json.load(f)["ctrl_panel"]
 
         param_tree_sigActivated_handles = [