diff --git a/src/Controller/S3CorsUploadAjaxController.php b/src/Controller/S3CorsUploadAjaxController.php
index fc62e6c..eb89fcb 100644
--- a/src/Controller/S3CorsUploadAjaxController.php
+++ b/src/Controller/S3CorsUploadAjaxController.php
@@ -79,8 +79,11 @@ class S3CorsUploadAjaxController extends ControllerBase {
       ['acl' => $post['acl']],
       ['bucket' => $bucket],
       ['starts-with', '$key', $destination . '/'],
+      ['Content-Disposition' => 'attachment; filename="' . $post['filename'] . '"'],
     ];
 
+    $post['Content-Disposition'] = 'attachment; filename="' . $post['filename'] . '"';
+
     // Retrieve the file name and build the URI.
     // Destination does not contain a prefix as it is applied by the fly system.
     $uri = \Drupal::service('file_system')->createFilename($post['filename'], $post['destination']);