diff --git a/src/Solver/CommandLine.py b/src/Solver/CommandLine.py
index 5f706d1a2772b25e6f10f82bd512bb7c574aaf78..18a237edc5a35ff39e1a44024df5650d443949f6 100644
--- a/src/Solver/CommandLine.py
+++ b/src/Solver/CommandLine.py
@@ -99,7 +99,10 @@ class CommandLineSolver(AbstractSolver):
         params = study.river.get_params(self.type)
         args = params.get_by_key("all_command_line_arguments")
 
-        return args.split(" ")
+        if args is None:
+            return []
+        else:
+            return args.split(" ")
 
     def input_param(self):
         """Return input command line parameter(s)