diff --git a/app/models/champs/piece_justificative_champ.rb b/app/models/champs/piece_justificative_champ.rb
index 708f17d24..eed62083b 100644
--- a/app/models/champs/piece_justificative_champ.rb
+++ b/app/models/champs/piece_justificative_champ.rb
@@ -43,7 +43,7 @@ class Champs::PieceJustificativeChamp < Champ
   end
 
   def for_export
-    piece_justificative_file.map { _1.filename.to_s }
+    piece_justificative_file.map { _1.filename.to_s }.join(', ')
   end
 
   def for_api
diff --git a/spec/models/champs/piece_justificative_champ_spec.rb b/spec/models/champs/piece_justificative_champ_spec.rb
index 1e0c9c80c..7861ad09a 100644
--- a/spec/models/champs/piece_justificative_champ_spec.rb
+++ b/spec/models/champs/piece_justificative_champ_spec.rb
@@ -43,11 +43,11 @@ describe Champs::PieceJustificativeChamp do
     let(:champ_pj) { create(:champ_piece_justificative) }
     subject { champ_pj.for_export }
 
-    it { is_expected.to match_array(['toto.txt']) }
+    it { is_expected.to eq('toto.txt') }
 
     context 'without attached file' do
       before { champ_pj.piece_justificative_file.purge }
-      it { is_expected.to eq([]) }
+      it { is_expected.to eq('') }
     end
   end