diff --git a/handler/FilesHandler.php b/handler/FilesHandler.php
index ae1ee65..e8da667 100644
--- a/handler/FilesHandler.php
+++ b/handler/FilesHandler.php
@@ -28,7 +28,7 @@ class FilesHandler extends request_handler {
         $folder = books_get_folder($folder_id);
         if (!$folder)
             not_found();
-        $files = books_get($folder_id);
+        $files = books_get($folder_id, category: $folder->category);
         add_meta([
             '$title' => lang('meta_files_book_folder_title', $folder->getTitle()),
             '$description' => lang('meta_files_book_folder_description', $folder->getTitle())
diff --git a/lib/files.php b/lib/files.php
index 64f0170..18cb834 100644
--- a/lib/files.php
+++ b/lib/files.php
@@ -626,6 +626,7 @@ class BookItem extends model implements FilesItemInterface {
     public BookFileType $fileType;
     public string $path;
     public bool $external;
+    public BookCategory $category;
 
     use FilesItemSizeTrait;
     use FilesItemTypeTrait;