diff --git a/app/controllers/experts/avis_controller.rb b/app/controllers/experts/avis_controller.rb
index c856fe2eb..393a18fae 100644
--- a/app/controllers/experts/avis_controller.rb
+++ b/app/controllers/experts/avis_controller.rb
@@ -17,7 +17,8 @@ module Experts
     end
 
     def procedure
-      @procedure = Procedure.find(params[:procedure_id])
+      @procedure = current_expert.procedures.find_by(id: params[:procedure_id])
+      redirect_to(expert_all_avis_path, flash: { alert: "Vous n’avez pas accès à cette démarche." }) and return unless @procedure
       expert_avis = current_expert.avis.includes(:dossier).not_hidden_by_administration.where(dossiers: { groupe_instructeur: GroupeInstructeur.where(procedure: @procedure.id) })
       @avis_a_donner = expert_avis.without_answer
       @avis_donnes = expert_avis.with_answer
@@ -156,7 +157,8 @@ module Experts
     end
 
     def set_avis_and_dossier
-      @avis = Avis.find(params[:id])
+      @avis = current_expert.avis.find_by(id: params[:id])
+      redirect_to(expert_all_avis_path, flash: { alert: "Vous n’avez pas accès à cet avis." }) and return unless @avis
       @dossier = @avis.dossier
     end
 
diff --git a/spec/controllers/experts/avis_controller_spec.rb b/spec/controllers/experts/avis_controller_spec.rb
index c81d0f472..f47d7607d 100644
--- a/spec/controllers/experts/avis_controller_spec.rb
+++ b/spec/controllers/experts/avis_controller_spec.rb
@@ -25,18 +25,31 @@ describe Experts::AvisController, type: :controller do
     end
 
     describe '#procedure' do
-      before { get :procedure, params: { procedure_id: procedure.id } }
+      context 'without filter' do
+        before { get :procedure, params: { procedure_id: procedure.id } }
 
-      it { expect(response).to have_http_status(:success) }
-      it { expect(assigns(:avis_a_donner)).to match([avis_without_answer]) }
-      it { expect(assigns(:avis_donnes)).to match([avis_with_answer]) }
-      it { expect(assigns(:statut)).to eq('a-donner') }
+        it { expect(response).to have_http_status(:success) }
+        it { expect(assigns(:avis_a_donner)).to match([avis_without_answer]) }
+        it { expect(assigns(:avis_donnes)).to match([avis_with_answer]) }
+        it { expect(assigns(:statut)).to eq('a-donner') }
+      end
 
       context 'with a statut equal to donnes' do
         before { get :procedure, params: { statut: 'donnes', procedure_id: procedure.id } }
 
         it { expect(assigns(:statut)).to eq('donnes') }
       end
+
+      context 'with different procedure' do
+        subject { get :procedure, params: { statut: 'donnes', procedure_id: procedure.id } }
+
+        it 'fails' do
+          sign_in(create(:expert).user)
+          subject
+          expect(response).to redirect_to(expert_all_avis_path)
+          expect(flash.alert).to eq("Vous n’avez pas accès à cette démarche.")
+        end
+      end
     end
 
     describe '#bilans_bdf' do
@@ -64,22 +77,52 @@ describe Experts::AvisController, type: :controller do
           expect(response).to redirect_to(root_path)
         end
       end
+
+      context 'with an avis that does not belongs to current_expert' do
+        it "refuse l'accès au dossier" do
+          sign_in(create(:expert).user)
+          subject
+          expect(response).to redirect_to(expert_all_avis_path)
+          expect(flash.alert).to eq("Vous n’avez pas accès à cet avis.")
+        end
+      end
     end
 
     describe '#instruction' do
-      before { get :instruction, params: { id: avis_without_answer.id, procedure_id: procedure.id } }
-
-      it { expect(response).to have_http_status(:success) }
-      it { expect(assigns(:avis)).to eq(avis_without_answer) }
-      it { expect(assigns(:dossier)).to eq(dossier) }
+      subject { get :instruction, params: { id: avis_without_answer.id, procedure_id: procedure.id } }
+      context 'with valid avis' do
+        before { subject }
+        it { expect(response).to have_http_status(:success) }
+        it { expect(assigns(:avis)).to eq(avis_without_answer) }
+        it { expect(assigns(:dossier)).to eq(dossier) }
+      end
+      context 'with an avis that does not belongs to current_expert' do
+        it "refuse l'accès au dossier" do
+          sign_in(create(:expert).user)
+          subject
+          expect(response).to redirect_to(expert_all_avis_path)
+          expect(flash.alert).to eq("Vous n’avez pas accès à cet avis.")
+        end
+      end
     end
 
     describe '#messagerie' do
-      before { get :messagerie, params: { id: avis_without_answer.id, procedure_id: procedure.id } }
+      subject { get :messagerie, params: { id: avis_without_answer.id, procedure_id: procedure.id } }
+      context 'with valid avis' do
+        before { subject }
 
-      it { expect(response).to have_http_status(:success) }
-      it { expect(assigns(:avis)).to eq(avis_without_answer) }
-      it { expect(assigns(:dossier)).to eq(dossier) }
+        it { expect(response).to have_http_status(:success) }
+        it { expect(assigns(:avis)).to eq(avis_without_answer) }
+        it { expect(assigns(:dossier)).to eq(dossier) }
+      end
+      context 'with an avis that does not belongs to current_expert' do
+        it "refuse l'accès au dossier" do
+          sign_in(create(:expert).user)
+          subject
+          expect(response).to redirect_to(expert_all_avis_path)
+          expect(flash.alert).to eq("Vous n’avez pas accès à cet avis.")
+        end
+      end
     end
 
     describe '#update' do
@@ -118,6 +161,14 @@ describe Experts::AvisController, type: :controller do
           expect(flash.notice).to eq('Votre réponse est enregistrée.')
         end
       end
+      context 'with an avis that does not belongs to current_expert' do
+        it "refuse l'accès au dossier" do
+          sign_in(create(:expert).user)
+          patch :update, params: { id: avis_without_answer.id, procedure_id: procedure.id, avis: { answer: 'answer' } }
+          expect(response).to redirect_to(expert_all_avis_path)
+          expect(flash.alert).to eq("Vous n’avez pas accès à cet avis.")
+        end
+      end
     end
 
     describe '#create_commentaire' do