diff --git a/app/models/export_template.rb b/app/models/export_template.rb
index f5ed164b9..3a9bf9c5c 100644
--- a/app/models/export_template.rb
+++ b/app/models/export_template.rb
@@ -48,7 +48,7 @@ class ExportTemplate < ApplicationRecord
   def attachment_and_path(dossier, attachment, index: 0, row_index: nil, champ: nil)
     [
       attachment,
-      path(dossier, attachment, index, row_index, champ)
+      path(dossier, attachment, index:, row_index:, champ:)
     ]
   end
 
@@ -116,7 +116,7 @@ class ExportTemplate < ApplicationRecord
     "#{render_attributes_for(content["pdf_name"], dossier)}.pdf"
   end
 
-  def path(dossier, attachment, index, row_index, champ)
+  def path(dossier, attachment, index: 0, row_index: nil, champ: nil)
     if attachment.name == 'pdf_export_for_instructeur'
       return export_path(dossier)
     end
diff --git a/app/services/pieces_justificatives_service.rb b/app/services/pieces_justificatives_service.rb
index 0fdbc2be9..8f95adc44 100644
--- a/app/services/pieces_justificatives_service.rb
+++ b/app/services/pieces_justificatives_service.rb
@@ -169,7 +169,12 @@ class PiecesJustificativesService
       .filter { |a| safe_attachment(a) }
       .map do |a|
         dossier_id = commentaire_id_dossier_id[a.record_id]
-        ActiveStorage::DownloadableFile.pj_and_path(dossier_id, a)
+        if @export_template
+          dossier = dossiers.find { _1.id == dossier_id }
+          @export_template.attachment_and_path(dossier, a)
+        else
+          ActiveStorage::DownloadableFile.pj_and_path(dossier_id, a)
+        end
       end
   end
 
diff --git a/spec/factories/export_template.rb b/spec/factories/export_template.rb
index 54ce224e5..d62754115 100644
--- a/spec/factories/export_template.rb
+++ b/spec/factories/export_template.rb
@@ -42,5 +42,27 @@ FactoryBot.define do
         export_template.save
       end
     end
+
+    trait :with_custom_ddd_prefix do
+      transient do
+        ddd_prefix { 'dossier_' }
+      end
+
+      to_create do |export_template, context|
+        export_template.set_default_values
+        export_template.content["default_dossier_directory"]["content"] = [
+          {
+            "type" => "paragraph",
+            "content" =>
+            [
+              { "text" => context.ddd_prefix, "type" => "text" },
+              { "type" => "mention", "attrs" => { "id" => "dossier_number", "label" => "numéro du dossier" } },
+              { "text" => " ", "type" => "text" }
+            ]
+          }
+        ]
+        export_template.save
+      end
+    end
   end
 end
diff --git a/spec/services/pieces_justificatives_service_spec.rb b/spec/services/pieces_justificatives_service_spec.rb
index bdfe28911..9d6e69fd1 100644
--- a/spec/services/pieces_justificatives_service_spec.rb
+++ b/spec/services/pieces_justificatives_service_spec.rb
@@ -164,6 +164,13 @@ describe PiecesJustificativesService do
         end
 
         it { expect(subject).to match_array(dossier.commentaires.first.piece_jointe.attachments) }
+
+        context 'with export_template' do
+          let(:export_template) { create(:export_template, :with_custom_ddd_prefix, ddd_prefix: "DOSSIER-", groupe_instructeur: procedure.defaut_groupe_instructeur) }
+          it 'uses specific name for dossier directory' do
+            expect(PiecesJustificativesService.new(user_profile:, export_template:).liste_documents(dossiers).map(&:second)[0].starts_with?("DOSSIER-#{dossier.id}/messagerie")).to be true
+          end
+        end
       end
 
       context 'with a pj not safe on a commentaire' do