diff --git a/swh/loader/package/deposit/loader.py b/swh/loader/package/deposit/loader.py
--- a/swh/loader/package/deposit/loader.py
+++ b/swh/loader/package/deposit/loader.py
@@ -117,7 +117,7 @@
         deposit_id: str,
         deposit_client: "ApiClient",
         max_content_size: Optional[int] = None,
-        default_filename: str = "archive.zip",
+        default_filename: str = "archive.tar",
     ):
         """Constructor
 
diff --git a/swh/loader/package/deposit/tests/test_deposit.py b/swh/loader/package/deposit/tests/test_deposit.py
--- a/swh/loader/package/deposit/tests/test_deposit.py
+++ b/swh/loader/package/deposit/tests/test_deposit.py
@@ -49,7 +49,7 @@
     url = "some-url"
     deposit_id = 999
     loader = DepositLoader(
-        swh_storage, url, deposit_id, deposit_client
+        swh_storage, url, deposit_id, deposit_client, default_filename="archive.zip"
     )  # Something that does not exist
 
     assert loader.url == url
@@ -61,7 +61,9 @@
     """Ensure the deposit instantiation is ok
 
     """
-    loader = DepositLoader.from_configfile(url="some-url", deposit_id="666")
+    loader = DepositLoader.from_configfile(
+        url="some-url", deposit_id="666", default_filename="archive.zip"
+    )
 
     assert isinstance(loader.client, ApiClient)
 
@@ -77,7 +79,11 @@
     url = "some-url"
     unknown_deposit_id = 667
     loader = DepositLoader(
-        swh_storage, url, unknown_deposit_id, deposit_client
+        swh_storage,
+        url,
+        unknown_deposit_id,
+        deposit_client,
+        default_filename="archive.zip",
     )  # does not exist
 
     actual_load_status = loader.load()
@@ -112,7 +118,9 @@
     url = "some-url-2"
     deposit_id = 666
     requests_mock_datadir_missing_one.put(re.compile("https"))
-    loader = DepositLoader(swh_storage, url, deposit_id, deposit_client)
+    loader = DepositLoader(
+        swh_storage, url, deposit_id, deposit_client, default_filename="archive.zip"
+    )
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
@@ -155,7 +163,9 @@
 ):
     url = "https://hal-test.archives-ouvertes.fr/some-external-id"
     deposit_id = 666
-    loader = DepositLoader(swh_storage, url, deposit_id, deposit_client)
+    loader = DepositLoader(
+        swh_storage, url, deposit_id, deposit_client, default_filename="archive.zip"
+    )
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
@@ -187,7 +197,9 @@
 def test_deposit_loading_ok(swh_storage, deposit_client, requests_mock_datadir):
     url = "https://hal-test.archives-ouvertes.fr/some-external-id"
     deposit_id = 666
-    loader = DepositLoader(swh_storage, url, deposit_id, deposit_client)
+    loader = DepositLoader(
+        swh_storage, url, deposit_id, deposit_client, default_filename="archive.zip"
+    )
 
     actual_load_status = loader.load()
     expected_snapshot_id = "b2b327b33dc85818bd23c3ccda8b7e675a66ecbd"
@@ -291,7 +303,9 @@
     external_id = "some-external-id"
     url = f"https://hal-test.archives-ouvertes.fr/{external_id}"
     deposit_id = 777
-    loader = DepositLoader(swh_storage, url, deposit_id, deposit_client)
+    loader = DepositLoader(
+        swh_storage, url, deposit_id, deposit_client, default_filename="archive.zip"
+    )
 
     actual_load_status = loader.load()
     expected_snapshot_id = "3e68440fdd7c81d283f8f3aebb6f0c8657864192"
@@ -490,9 +504,7 @@
     external_id = "hal-123456"
     url = f"https://hal-test.archives-ouvertes.fr/{external_id}"
     deposit_id = 888
-    loader = DepositLoader(
-        swh_storage, url, deposit_id, deposit_client, default_filename="archive.tar"
-    )
+    loader = DepositLoader(swh_storage, url, deposit_id, deposit_client)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "0ac7b54c042a026389f2087dc16f1d5c644ed0e4"