diff --git a/app/javascript/new_design/dossiers/auto-upload-controller.js b/app/javascript/new_design/dossiers/auto-upload-controller.js
index 3707f4078..b26601468 100644
--- a/app/javascript/new_design/dossiers/auto-upload-controller.js
+++ b/app/javascript/new_design/dossiers/auto-upload-controller.js
@@ -23,18 +23,12 @@ export default class AutoUploadController {
         throw new Error('L’attribut "data-auto-attach-url" est manquant');
       }
 
-      const champ = this.input.closest('.editable-champ[data-champ-id]');
-      if (!champ) {
-        throw new Error('Impossible de trouver l’élément ".editable-champ"');
-      }
-      const champId = champ.dataset.champId;
-
       // Upload the file (using Direct Upload)
       let blobSignedId = await this._upload();
 
       // Attach the blob to the champ
       // (The request responds with Javascript, which displays the attachment HTML fragment).
-      await this._attach(champId, blobSignedId, autoAttachUrl);
+      await this._attach(blobSignedId, autoAttachUrl);
 
       // Everything good: clear the original file input value
       this.input.value = null;
@@ -60,10 +54,14 @@ export default class AutoUploadController {
     return await uploader.start();
   }
 
-  async _attach(champId, blobSignedId, autoAttachUrl) {
+  async _attach(blobSignedId, autoAttachUrl) {
     // Now that the upload is done, display a new progress bar
     // to show that the attachment request is still pending.
-    const progressBar = new ProgressBar(this.input, champId, this.file);
+    const progressBar = new ProgressBar(
+      this.input,
+      `${this.input.id}-progress-bar`,
+      this.file
+    );
     progressBar.progress(100);
     progressBar.end();