diff --git a/backend/app/Controllers/ElementController.php b/backend/app/Controllers/ElementController.php
index 31fd90c..5fc14d7 100644
--- a/backend/app/Controllers/ElementController.php
+++ b/backend/app/Controllers/ElementController.php
@@ -69,8 +69,8 @@ class ElementController
     }
 
     public function showPdf(
-        string $folder,
-        string $fileName,
+        ?string $folder,
+        ?string $fileName,
     ): Response|JsonResponse {
         try {
             $result = $this->getElementPdf->execute(
@@ -79,6 +79,10 @@ class ElementController
                     fileName: $fileName,
                 )
             );
+        } catch (BadRequestException $exception) {
+            return new JsonResponse([
+                'error' => $exception->getMessage(),
+            ], 400);
         } catch (NotFoundException $exception) {
             return new JsonResponse([
                 'error' => $exception->getMessage(),
diff --git a/backend/app/Element/UseCases/GetElementPdf/GetElementPdf.php b/backend/app/Element/UseCases/GetElementPdf/GetElementPdf.php
index a742ac3..e210c61 100644
--- a/backend/app/Element/UseCases/GetElementPdf/GetElementPdf.php
+++ b/backend/app/Element/UseCases/GetElementPdf/GetElementPdf.php
@@ -2,6 +2,7 @@
 
 namespace App\Element\UseCases\GetElementPdf;
 
+use App\Exceptions\BadRequestException;
 use App\Exceptions\NotFoundException;
 use App\Shared\Files\Filesystem;
 
@@ -16,10 +17,19 @@ class GetElementPdf
     }
 
     /**
+     * @throws BadRequestException
      * @throws NotFoundException
      */
     public function execute(GetElementPdfRequest $request): GetElementPdfResult
     {
+        if ($request->folder === null) {
+            throw new BadRequestException('folder is required');
+        }
+
+        if ($request->fileName === null) {
+            throw new BadRequestException('fileName is required');
+        }
+
         if (!$this->isAllowedPdfFolder($request->folder)) {
             throw new NotFoundException('PDF not found');
         }
diff --git a/backend/app/Element/UseCases/GetElementPdf/GetElementPdfRequest.php b/backend/app/Element/UseCases/GetElementPdf/GetElementPdfRequest.php
index 8824afd..ba7b565 100644
--- a/backend/app/Element/UseCases/GetElementPdf/GetElementPdfRequest.php
+++ b/backend/app/Element/UseCases/GetElementPdf/GetElementPdfRequest.php
@@ -5,8 +5,8 @@ namespace App\Element\UseCases\GetElementPdf;
 class GetElementPdfRequest
 {
     public function __construct(
-        public string $folder,
-        public string $fileName,
+        public ?string $folder,
+        public ?string $fileName,
     ) {
     }
 }