diff --git a/pathfinderevents.py b/pathfinderevents.py
index b91d024..64ffdec 100644
--- a/pathfinderevents.py
+++ b/pathfinderevents.py
@@ -179,11 +179,14 @@ def _key_mapper(ce: CloudEvent) -> Any | None:  # noqa: ANN401
             ce,
             key_mapper=_key_mapper,
         )
+        headers: list[tuple[str, bytes]] | None
+        if kafka_msg.headers:
+            headers = list(kafka_msg.headers.items())
         self.producer.send(
             self.topic,
             key=kafka_msg.key,
             value=kafka_msg.value,
-            headers=kafka_msg.headers if kafka_msg.headers else None,
+            headers=headers,
         ).add_errback(on_send_error)
         self.producer.flush()
         logger.info(
diff --git a/tests/test_pathfinderevents.py b/tests/test_pathfinderevents.py
index fa2f32b..ceea6b9 100644
--- a/tests/test_pathfinderevents.py
+++ b/tests/test_pathfinderevents.py
@@ -106,7 +106,7 @@ def test_api_webhook(mock_producer, mock_api, mock_sys_exit):  # noqa: ARG001
         "test",
         key="ch.rabe.api.events.pathfinder.v0alpha1.OnAir.Klangbecken",
         value=ANY,
-        headers={"content-type": b"text/plain"},
+        headers=[("content-type", b"text/plain")],
     )
     value = json.loads(mock_producer.send.call_args.kwargs["value"])
     assert value["data"] == "Klangbecken"