diff --git a/app/models/champs/piece_justificative_champ.rb b/app/models/champs/piece_justificative_champ.rb
index b7aa201f6..bfa5c2473 100644
--- a/app/models/champs/piece_justificative_champ.rb
+++ b/app/models/champs/piece_justificative_champ.rb
@@ -35,9 +35,8 @@ class Champs::PieceJustificativeChamp < Champ
 
   validates :piece_justificative_file,
     content_type: ACCEPTED_FORMATS,
-    size: { less_than: MAX_SIZE }
-
-  before_save :update_skip_pj_validation
+    size: { less_than: MAX_SIZE },
+    if: -> { !type_de_champ.skip_pj_validation }
 
   def main_value_name
     :piece_justificative_file
@@ -60,8 +59,4 @@ class Champs::PieceJustificativeChamp < Champ
       piece_justificative_file.service_url
     end
   end
-
-  def update_skip_pj_validation
-    type_de_champ.update(skip_pj_validation: true)
-  end
 end
diff --git a/spec/features/users/brouillon_spec.rb b/spec/features/users/brouillon_spec.rb
index 5818f99e8..898af7cb0 100644
--- a/spec/features/users/brouillon_spec.rb
+++ b/spec/features/users/brouillon_spec.rb
@@ -176,6 +176,13 @@ feature 'The user' do
     create(:procedure, :published, :for_individual, types_de_champ: tdcs)
   end
 
+  let(:old_procedure_with_disabled_pj_validation) do
+    tdcs = [
+      create(:type_de_champ_piece_justificative, mandatory: true, libelle: 'Pièce justificative 1', order_place: 1, skip_pj_validation: true)
+    ]
+    create(:procedure, :published, :for_individual, types_de_champ: tdcs)
+  end
+
   scenario 'add an attachment', js: true do
     log_in(user, procedure_with_pjs)
     fill_individual
@@ -216,6 +223,16 @@ feature 'The user' do
     expect(page).to have_text('piece_justificative_0.pdf')
   end
 
+  scenario 'add an invalid attachment on an old procedure where pj validation is disabled', js: true do
+    log_in(user, old_procedure_with_disabled_pj_validation)
+    fill_individual
+
+    # Test invalid file type
+    attach_file('Pièce justificative 1', Rails.root + 'spec/fixtures/files/invalid_file_format.json')
+    expect(page).to have_no_text('La pièce justificative n’est pas d’un type accepté')
+    expect(page).to have_text('analyse antivirus en cours', count: 1)
+  end
+
   scenario 'retry on transcient upload error', js: true do
     log_in(user, procedure_with_pjs)
     fill_individual
diff --git a/spec/models/champs/piece_justificative_champ_spec.rb b/spec/models/champs/piece_justificative_champ_spec.rb
index 7f5a563e8..b8cacf149 100644
--- a/spec/models/champs/piece_justificative_champ_spec.rb
+++ b/spec/models/champs/piece_justificative_champ_spec.rb
@@ -3,7 +3,7 @@ require 'active_storage_validations/matchers'
 describe Champs::PieceJustificativeChamp do
   include ActiveStorageValidations::Matchers
 
-  describe "update_skip_validation" do
+  describe "skip_validation is not set anymore" do
     subject { champ_pj.type_de_champ.skip_pj_validation }
 
     context 'before_save' do
@@ -12,15 +12,26 @@ describe Champs::PieceJustificativeChamp do
     end
     context 'after_save' do
       let(:champ_pj) { create (:champ_piece_justificative) }
-      it { is_expected.to be_truthy }
+      it { is_expected.to be_falsy }
     end
   end
 
   describe "validations" do
-    subject(:champ_pj) { build(:champ_piece_justificative) }
+    let(:champ_pj) { create(:champ_piece_justificative) }
+    subject { champ_pj }
 
-    it { is_expected.to validate_size_of(:piece_justificative_file).less_than(Champs::PieceJustificativeChamp::MAX_SIZE) }
-    it { is_expected.to validate_content_type_of(:piece_justificative_file).allowing(Champs::PieceJustificativeChamp::ACCEPTED_FORMATS) }
+    context "by default" do
+      it { is_expected.to validate_size_of(:piece_justificative_file).less_than(Champs::PieceJustificativeChamp::MAX_SIZE) }
+      it { is_expected.to validate_content_type_of(:piece_justificative_file).allowing(Champs::PieceJustificativeChamp::ACCEPTED_FORMATS) }
+      it { expect(champ_pj.type_de_champ.skip_pj_validation).to be_falsy }
+    end
+
+    context "when validation is disabled" do
+      before { champ_pj.type_de_champ.update(skip_pj_validation: true) }
+
+      it { is_expected.not_to validate_size_of(:piece_justificative_file).less_than(Champs::PieceJustificativeChamp::MAX_SIZE) }
+      it { is_expected.not_to validate_content_type_of(:piece_justificative_file).allowing(Champs::PieceJustificativeChamp::ACCEPTED_FORMATS) }
+    end
   end
 
   describe "#for_export" do