diff --git a/releasenotes/notes/return-error-400-on-bad-parameters-bb964e4f5cadc15c.yaml b/releasenotes/notes/return-error-400-on-bad-parameters-bb964e4f5cadc15c.yaml
new file mode 100644
index 000000000..9c920f2ed
--- /dev/null
+++ b/releasenotes/notes/return-error-400-on-bad-parameters-bb964e4f5cadc15c.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    `Bug #2110538 <https://bugs.launchpad.net/watcher/+bug/2110538>`_:
+    Corrected the HTTP error code returned when watcher users try to create
+    audits with invalid parameters. The API now correctly returns a 400 Bad
+    Request error.
diff --git a/watcher/api/controllers/v1/audit.py b/watcher/api/controllers/v1/audit.py
index 70c825e27..366e7c628 100644
--- a/watcher/api/controllers/v1/audit.py
+++ b/watcher/api/controllers/v1/audit.py
@@ -33,6 +33,7 @@ import datetime
 from dateutil import tz
 
 from http import HTTPStatus
+import jsonschema
 from oslo_log import log
 from oslo_utils import timeutils
 import pecan
@@ -627,8 +628,12 @@ class AuditsController(rest.RestController):
             if schema:
                 # validate input parameter with default value feedback
                 no_schema = False
-                utils.StrictDefaultValidatingDraft4Validator(schema).validate(
-                    audit.parameters)
+                try:
+                    utils.StrictDefaultValidatingDraft4Validator(
+                        schema).validate(audit.parameters)
+                except jsonschema.exceptions.ValidationError as e:
+                    raise exception.Invalid(
+                        _('Invalid parameters for strategy: %s') % e)
 
         if no_schema and audit.parameters:
             raise exception.Invalid(_('Specify parameters but no predefined '
diff --git a/watcher/tests/api/v1/test_audits.py b/watcher/tests/api/v1/test_audits.py
index adcf46afc..c536be871 100644
--- a/watcher/tests/api/v1/test_audits.py
+++ b/watcher/tests/api/v1/test_audits.py
@@ -843,16 +843,12 @@ class TestPost(api_base.FunctionalTest):
             del audit_dict[k]
 
         response = self.post_json('/audits', audit_dict, expect_errors=True)
-        # (amoralej) This should return HTTPStatus.BAD_REQUEST, however this
-        # review is adding the test to show wrong code is returned. I will
-        # switch this to be HTTPStatus.BAD_REQUEST in the fixing review.
-        self.assertEqual(HTTPStatus.INTERNAL_SERVER_ERROR, response.status_int)
+        self.assertEqual(HTTPStatus.BAD_REQUEST, response.status_int)
         self.assertEqual("application/json", response.content_type)
-        # (amoralej) uncomment with the fix
-        # expected_error_msg = (
-        #    "Invalid parameters for strategy: 'fake1' is a required property")
-        # self.assertTrue(response.json['error_message'])
-        # self.assertIn(expected_error_msg, response.json['error_message'])
+        expected_error_msg = (
+            "Invalid parameters for strategy: 'fake1' is a required property")
+        self.assertTrue(response.json['error_message'])
+        self.assertIn(expected_error_msg, response.json['error_message'])
         assert not mock_trigger_audit.called
 
     def prepare_audit_template_strategy_with_parameter(self):