diff --git a/swh/web/common/service.py b/swh/web/common/service.py
--- a/swh/web/common/service.py
+++ b/swh/web/common/service.py
@@ -297,14 +297,16 @@
         directory information as dict.
 
     """
+    empty_dir_sha1 = hashutil.hash_to_bytes(
+        '4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+    )
     sha1_git_bin = _to_sha1_bin(sha1_git)
 
-    dir = _first_element(storage.directory_get([sha1_git_bin]))
-    if not dir:
-        raise NotFoundExc('Directory with sha1_git %s not found' % sha1_git)
-
     directory_entries = storage.directory_ls(sha1_git_bin) or []
-    return map(converters.from_directory_entry, directory_entries)
+    if directory_entries or sha1_git_bin == empty_dir_sha1:
+        return map(converters.from_directory_entry, directory_entries)
+    else:
+        raise NotFoundExc('Directory with sha1_git %s not found' % sha1_git)
 
 
 def lookup_directory_with_path(directory_sha1_git, path_string):
diff --git a/swh/web/tests/common/test_service.py b/swh/web/tests/common/test_service.py
--- a/swh/web/tests/common/test_service.py
+++ b/swh/web/tests/common/test_service.py
@@ -1702,19 +1702,19 @@
         mock_query.parse_hash_with_algorithms_or_throws.return_value = (
             'sha1',
             'directory-id-bin')
-        mock_storage.directory_get.return_value = None
+        mock_storage.directory_ls.return_value = []
 
         # when
         with self.assertRaises(NotFoundExc) as cm:
             service.lookup_directory('directory_id')
-            self.assertIn('Directory with sha1_git directory_id not found',
-                          cm.exception.args[0])
+
+        self.assertIn('Directory with sha1_git directory_id not found',
+                      cm.exception.args[0])
 
         # then
         mock_query.parse_hash_with_algorithms_or_throws.assert_called_with(
             'directory_id', ['sha1'], 'Only sha1_git is supported.')
-        mock_storage.directory_get.assert_called_with(['directory-id-bin'])
-        mock_storage.directory_ls.called = False
+        mock_storage.directory_ls.assert_called_with('directory-id-bin')
 
     @patch('swh.web.common.service.storage')
     @patch('swh.web.common.service.query')
@@ -1724,9 +1724,6 @@
             'sha1',
             'directory-sha1-bin')
 
-        # something that exists is all that matters here
-        mock_storage.directory_get.return_value = {'id': b'directory-sha1-bin'}
-
         # given
         stub_dir_entries = [{
             'sha1': self.SHA1_SAMPLE_BIN,
@@ -1767,6 +1764,22 @@
         mock_storage.directory_ls.assert_called_with(
             'directory-sha1-bin')
 
+    @patch('swh.web.common.service.storage')
+    @istest
+    def lookup_directory_empty(self, mock_storage):
+        empty_dir_sha1 = '4b825dc642cb6eb9a060e54bf8d69288fbee4904'
+        mock_storage.directory_ls.return_value = []
+
+        # when
+        actual_directory_ls = list(service.lookup_directory(empty_dir_sha1))
+
+        # then
+        self.assertEqual(actual_directory_ls, [])
+
+        mock_storage.directory_ls.assert_called_with(
+            bytes.fromhex(empty_dir_sha1)
+        )
+
     @patch('swh.web.common.service.storage')
     @istest
     def lookup_revision_by_nothing_found(self, mock_storage):