diff --git a/src/borg/helpers/parseformat.py b/src/borg/helpers/parseformat.py
index cdfb145ac..9dfda8d24 100644
--- a/src/borg/helpers/parseformat.py
+++ b/src/borg/helpers/parseformat.py
@@ -227,7 +227,7 @@ def SortBySpec(text):
     from .manifest import AI_HUMAN_SORT_KEYS
     for token in text.split(','):
         if token not in AI_HUMAN_SORT_KEYS:
-            raise ValueError('Invalid sort key: %s' % token)
+            raise argparse.ArgumentTypeError('Invalid sort key: %s' % token)
     return text.replace('timestamp', 'ts')