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
 
diff --git a/spec/services/procedure_export_service_spec.rb b/spec/services/procedure_export_service_spec.rb
index a0e737a7d..43c9c517a 100644
--- a/spec/services/procedure_export_service_spec.rb
+++ b/spec/services/procedure_export_service_spec.rb
@@ -98,6 +98,7 @@ describe ProcedureExportService do
         offset = dossier.depose_at.utc_offset
         depose_at = Time.zone.at(dossiers_sheet.data[0][8] - offset.seconds)
         en_instruction_at = Time.zone.at(dossiers_sheet.data[0][9] - offset.seconds)
+        expect(dossiers_sheet.data.first.size).to eq(nominal_headers.size)
         expect(depose_at).to eq(dossier.depose_at.round)
         expect(en_instruction_at).to eq(dossier.en_instruction_at.round)
       end
@@ -119,6 +120,17 @@ describe ProcedureExportService do
         it { expect(dossiers_sheet.headers).to match(routee_headers) }
         it { expect(dossiers_sheet.data[0][dossiers_sheet.headers.index('Groupe instructeur')]).to eq('défaut') }
       end
+
+      context 'with a dossier having multiple pjs' do
+        let!(:dossier_2) { create(:dossier, :en_instruction, :with_populated_champs, :with_individual, procedure: procedure) }
+        before do
+          dossier_2.champs_public
+            .find { _1.is_a? Champs::PieceJustificativeChamp }
+            .piece_justificative_file
+            .attach(io: StringIO.new("toto"), filename: "toto.txt", content_type: "text/plain")
+        end
+        it { expect(dossiers_sheet.data.first.size).to eq(nominal_headers.size) }
+      end
     end
 
     describe 'Etablissement sheet' do