diff --git a/app/models/attestation_template.rb b/app/models/attestation_template.rb
index 8b1e9d792..db966a89f 100644
--- a/app/models/attestation_template.rb
+++ b/app/models/attestation_template.rb
@@ -68,7 +68,7 @@ class AttestationTemplate < ApplicationRecord
       body: dossier ? replace_tags(body, dossier) : params.fetch(:body, body),
       footer: params.fetch(:footer, footer),
       logo: params.fetch(:logo, logo.attached? ? logo : nil),
-      signature: params.fetch(:signature, signature.attached? ? signature : nil)
+      signature: signature_to_render(params)
     }
   end
 
@@ -90,6 +90,16 @@ class AttestationTemplate < ApplicationRecord
 
   private
 
+  def signature_to_render(params)
+    dossier = params.fetch(:dossier, false)
+    groupe_instructeur = dossier ? dossier.groupe_instructeur : params[:groupe_instructeur]
+    if groupe_instructeur && groupe_instructeur.signature.attached?
+      groupe_instructeur.signature
+    else
+      signature
+    end
+  end
+
   def used_tags
     used_tags_for(title) + used_tags_for(body)
   end
diff --git a/app/models/groupe_instructeur.rb b/app/models/groupe_instructeur.rb
index 1d0af0c7b..d14434586 100644
--- a/app/models/groupe_instructeur.rb
+++ b/app/models/groupe_instructeur.rb
@@ -15,6 +15,11 @@ class GroupeInstructeur < ApplicationRecord
   has_one :defaut_procedure, -> { with_discarded }, class_name: 'Procedure', foreign_key: :defaut_groupe_instructeur_id, dependent: :nullify, inverse_of: :defaut_groupe_instructeur
   has_one :contact_information
 
+  has_one_attached :signature
+
+  SIGNATURE_MAX_SIZE = 1.megabytes
+  validates :signature, content_type: ['image/png', 'image/jpg', 'image/jpeg'], size: { less_than: SIGNATURE_MAX_SIZE }
+
   validates :label, presence: true, allow_nil: false
   validates :label, uniqueness: { scope: :procedure }
   validates :closed, acceptance: { accept: [false] }, if: -> { (self == procedure.defaut_groupe_instructeur) }
diff --git a/spec/controllers/administrateurs/attestation_templates_controller_spec.rb b/spec/controllers/administrateurs/attestation_templates_controller_spec.rb
index 0e670de35..a1930f1d5 100644
--- a/spec/controllers/administrateurs/attestation_templates_controller_spec.rb
+++ b/spec/controllers/administrateurs/attestation_templates_controller_spec.rb
@@ -58,7 +58,7 @@ describe Administrateurs::AttestationTemplatesController, type: :controller do
           expect(assigns(:attestation)).to include(attestation_params)
           expect(assigns(:attestation)[:created_at]).to eq(Time.zone.now)
           expect(assigns(:attestation)[:logo]).to eq(nil)
-          expect(assigns(:attestation)[:signature]).to eq(nil)
+          expect(assigns(:attestation)[:signature]).not_to be_attached
         end
         it_behaves_like 'rendering a PDF successfully'
       end
diff --git a/spec/models/attestation_template_spec.rb b/spec/models/attestation_template_spec.rb
index 3f307c2f8..e47f596a7 100644
--- a/spec/models/attestation_template_spec.rb
+++ b/spec/models/attestation_template_spec.rb
@@ -1,45 +1,4 @@
 describe AttestationTemplate, type: :model do
-  # describe 'validate' do
-  #   let(:logo_size) { AttestationTemplate::FILE_MAX_SIZE_IN_MB.megabyte }
-  #   let(:signature_size) { AttestationTemplate::FILE_MAX_SIZE_IN_MB.megabyte }
-  #   let(:fake_logo) { double(AttestationTemplateLogoUploader, file: double(size: logo_size)) }
-  #   let(:fake_signature) { double(AttestationTemplateSignatureUploader, file: double(size: signature_size)) }
-  #   let(:attestation_template) { AttestationTemplate.new }
-
-  #   before do
-  #     allow(attestation_template).to receive(:logo).and_return(fake_logo)
-  #     allow(attestation_template).to receive(:signature).and_return(fake_signature)
-  #     attestation_template.validate
-  #   end
-
-  #   subject { attestation_template.errors.details }
-
-  #   context 'when no files are present' do
-  #     let(:fake_logo) { nil }
-  #     let(:fake_signature) { nil }
-
-  #     it { is_expected.to match({}) }
-  #   end
-
-  #   context 'when the logo and the signature have the right size' do
-  #     it { is_expected.to match({}) }
-  #   end
-
-  #   context 'when the logo and the signature are too heavy' do
-  #     let(:logo_size) { AttestationTemplate::FILE_MAX_SIZE_IN_MB.megabyte + 1 }
-  #     let(:signature_size) { AttestationTemplate::FILE_MAX_SIZE_IN_MB.megabyte + 1 }
-
-  #     it do
-  #       expected = {
-  #         signature: [{ error: ' : vous ne pouvez pas charger une image de plus de 0,5 Mo' }],
-  #         logo: [{ error: ' : vous ne pouvez pas charger une image de plus de 0,5 Mo' }]
-  #       }
-
-  #       is_expected.to match(expected)
-  #     end
-  #   end
-  # end
-
   describe 'validates footer length' do
     let(:attestation_template) { build(:attestation_template, footer: footer) }
 
@@ -175,4 +134,44 @@ describe AttestationTemplate, type: :model do
       end
     end
   end
+
+  describe '#render_attributes_for' do
+    context 'signature' do
+      let(:dossier) { create(:dossier, procedure: attestation.procedure, groupe_instructeur: groupe_instructeur) }
+
+      subject { attestation.render_attributes_for(dossier: dossier)[:signature] }
+
+      context 'procedure with signature' do
+        let(:attestation) { create(:attestation_template, signature: Rack::Test::UploadedFile.new('spec/fixtures/files/logo_test_procedure.png', 'image/png')) }
+
+        context "groupe instructeur without signature" do
+          let(:groupe_instructeur) { create(:groupe_instructeur, signature: nil) }
+
+          it { expect(subject.blob.filename).to eq("logo_test_procedure.png") }
+        end
+
+        context 'groupe instructeur with signature' do
+          let(:groupe_instructeur) { create(:groupe_instructeur, signature: Rack::Test::UploadedFile.new('spec/fixtures/files/black.png', 'image/png')) }
+
+          it { expect(subject.blob.filename).to eq("black.png") }
+        end
+      end
+
+      context 'procedure without signature' do
+        let(:attestation) { create(:attestation_template, signature: nil) }
+
+        context "groupe instructeur without signature" do
+          let(:groupe_instructeur) { create(:groupe_instructeur, signature: nil) }
+
+          it { expect(subject.attached?).to be_falsey }
+        end
+
+        context 'groupe instructeur with signature' do
+          let(:groupe_instructeur) { create(:groupe_instructeur, signature: Rack::Test::UploadedFile.new('spec/fixtures/files/black.png', 'image/png')) }
+
+          it { expect(subject.blob.filename).to eq("black.png") }
+        end
+      end
+    end
+  end
 end