diff --git a/attachment_swift/tests/test_mock_swift_api.py b/attachment_swift/tests/test_mock_swift_api.py
index 9bea70d..205e284 100644
--- a/attachment_swift/tests/test_mock_swift_api.py
+++ b/attachment_swift/tests/test_mock_swift_api.py
@@ -2,6 +2,7 @@
 # Copyright 2017 Camptocamp SA
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
 
+import base64
 import os
 
 from mock import patch
@@ -46,7 +47,7 @@ class TestAttachmentSwift(TestIrAttachment):
         os.environ['SWIFT_WRITE_CONTAINER'] = 'my_container'
         container = os.environ.get('SWIFT_WRITE_CONTAINER')
         attachment = self.Attachment
-        bin_data = self.blob1_b64.decode('base64')
+        bin_data = base64.b64decode(self.blob1_b64)
         with patch('swiftclient.client.Connection') as MockConnection:
             conn = MockConnection.return_value
             attachment.create({'name': 'a5', 'datas': self.blob1_b64})
diff --git a/base_attachment_object_storage/models/ir_attachment.py b/base_attachment_object_storage/models/ir_attachment.py
index 9063cc6..64f800a 100644
--- a/base_attachment_object_storage/models/ir_attachment.py
+++ b/base_attachment_object_storage/models/ir_attachment.py
@@ -3,6 +3,7 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html)
 
 
+import base64
 import logging
 import os
 import psycopg2
@@ -61,7 +62,7 @@ class IrAttachment(models.Model):
             if location in self._get_stores() and attach._save_in_db_anyway():
                 # compute the fields that depend on datas
                 value = attach.datas
-                bin_data = value and value.decode('base64') or ''
+                bin_data = base64.b64decode(value) if value else ''
                 vals = {
                     'file_size': len(bin_data),
                     'checksum': self._compute_checksum(bin_data),
@@ -107,7 +108,7 @@ class IrAttachment(models.Model):
     @api.model
     def _file_write(self, value, checksum):
         if self._storage() in self._get_stores():
-            bin_data = value.decode('base64')
+            bin_data = base64.b64decode(value)
             key = self._compute_checksum(bin_data)
             filename = self._store_file_write(key, bin_data)
         else: