diff --git a/app/models/dossier.rb b/app/models/dossier.rb
index 1cca19ee4..9fe7a7242 100644
--- a/app/models/dossier.rb
+++ b/app/models/dossier.rb
@@ -289,30 +289,13 @@ class Dossier < ApplicationRecord
   scope :for_api_v2, -> { includes(procedure: [:administrateurs], etablissement: [], individual: [], traitements: []) }
 
   scope :with_notifications, -> do
-    # This scope is meant to be composed, typically with Instructeur.followed_dossiers, which means that the :follows table is already INNER JOINed;
-    # it will fail otherwise
-    # rubocop:disable DS/ApplicationName
-    joined_dossiers = joins('LEFT OUTER JOIN "champs" ON "champs" . "dossier_id" = "dossiers" . "id" AND "champs" . "parent_id" IS NULL AND "champs" . "private" = FALSE AND "champs"."updated_at" > "follows"."demande_seen_at"')
-      .joins('LEFT OUTER JOIN "champs" "champs_privates_dossiers" ON "champs_privates_dossiers" . "dossier_id" = "dossiers" . "id" AND "champs_privates_dossiers" . "parent_id" IS NULL AND "champs_privates_dossiers" . "private" = TRUE AND "champs_privates_dossiers"."updated_at" > "follows"."annotations_privees_seen_at"')
-      .joins('LEFT OUTER JOIN "avis" ON "avis" . "dossier_id" = "dossiers" . "id" AND avis.updated_at > follows.avis_seen_at')
-      .joins('LEFT OUTER JOIN "commentaires" ON "commentaires" . "dossier_id" = "dossiers" . "id" and commentaires.updated_at > follows.messagerie_seen_at and "commentaires"."email" != \'contact@tps.apientreprise.fr\' AND "commentaires"."email" != \'contact@demarches-simplifiees.fr\'')
-    # rubocop:enable DS/ApplicationName
-
-    updated_demandes = joined_dossiers
-      .where('champs.updated_at > follows.demande_seen_at OR groupe_instructeur_updated_at > follows.demande_seen_at')
-
-    updated_annotations = joined_dossiers
-      .where('champs_privates_dossiers.updated_at > follows.annotations_privees_seen_at')
-
-    updated_avis = joined_dossiers
-      .where('avis.updated_at > follows.avis_seen_at')
-
-    updated_messagerie = joined_dossiers
-      .where('commentaires.updated_at > follows.messagerie_seen_at')
-      .where.not(commentaires: { email: OLD_CONTACT_EMAIL })
-      .where.not(commentaires: { email: CONTACT_EMAIL })
-
-    updated_demandes.or(updated_annotations).or(updated_avis).or(updated_messagerie).distinct
+    joins(:follows)
+      .where('last_champ_updated_at > follows.demande_seen_at' \
+      ' OR groupe_instructeur_updated_at > follows.demande_seen_at' \
+      ' OR last_champ_private_updated_at > follows.annotations_privees_seen_at' \
+      ' OR last_avis_updated_at > follows.avis_seen_at' \
+      ' OR last_commentaire_updated_at > follows.messagerie_seen_at')
+      .distinct
   end
 
   accepts_nested_attributes_for :individual
diff --git a/spec/models/dossier_spec.rb b/spec/models/dossier_spec.rb
index 4a61017a0..ff6cffc32 100644
--- a/spec/models/dossier_spec.rb
+++ b/spec/models/dossier_spec.rb
@@ -112,9 +112,29 @@ describe Dossier do
     end
 
     context('with changes') do
-      before { dossier.commentaires << create(:commentaire, email: 'test@exemple.fr') }
+      context 'when there is a new commentaire' do
+        before { dossier.update!(last_commentaire_updated_at: Time.zone.now) }
 
-      it { is_expected.to match([dossier]) }
+        it { is_expected.to match([dossier]) }
+      end
+
+      context 'when there is a new avis' do
+        before { dossier.update!(last_avis_updated_at: Time.zone.now) }
+
+        it { is_expected.to match([dossier]) }
+      end
+
+      context 'when a public champ is updated' do
+        before { dossier.update!(last_champ_updated_at: Time.zone.now) }
+
+        it { is_expected.to match([dossier]) }
+      end
+
+      context 'when a private champ is updated' do
+        before { dossier.update!(last_champ_private_updated_at: Time.zone.now) }
+
+        it { is_expected.to match([dossier]) }
+      end
     end
   end
 
diff --git a/spec/models/instructeur_spec.rb b/spec/models/instructeur_spec.rb
index e6db4ed56..c8ed17993 100644
--- a/spec/models/instructeur_spec.rb
+++ b/spec/models/instructeur_spec.rb
@@ -263,12 +263,20 @@ describe Instructeur, type: :model do
 
     let!(:dossier_on_procedure_2) { create(:dossier, :followed, state: Dossier.states.fetch(:en_construction)) }
     let!(:instructeur_on_procedure_2) { dossier_on_procedure_2.follows.first.instructeur }
+    let(:now) { Time.zone.parse("14/09/1867") }
+    let(:follow) { instructeur.follows.find_by(dossier: dossier) }
+    let(:follow2) { instructeur_2.follows.find_by(dossier: dossier) }
+    let(:seen_at_instructeur) { now - 1.hour }
+    let(:seen_at_instructeur2) { now - 1.hour }
 
     before do
       procedure.groupe_instructeurs.last.instructeurs << instructeur
       instructeur_2.followed_dossiers << dossier
+      Timecop.freeze(now)
     end
 
+    after { Timecop.return }
+
     subject { instructeur.notifications_for_procedure(procedure, :en_cours) }
 
     context 'when the instructeur has just followed the dossier' do
@@ -276,7 +284,11 @@ describe Instructeur, type: :model do
     end
 
     context 'when there is a modification on public champs' do
-      before { dossier.champs.first.update_attribute('value', 'toto') }
+      before do
+        dossier.update!(last_champ_updated_at: now)
+        follow.update_attribute('demande_seen_at', seen_at_instructeur)
+        follow2.update_attribute('demande_seen_at', seen_at_instructeur2)
+      end
 
       it { is_expected.to match([dossier]) }
       it { expect(instructeur_2.notifications_for_procedure(procedure, :en_cours)).to match([dossier]) }
@@ -289,9 +301,8 @@ describe Instructeur, type: :model do
       end
 
       context 'when instructeur update it s public champs last seen' do
-        let(:follow) { instructeur.follows.find_by(dossier: dossier) }
-
-        before { follow.update_attribute('demande_seen_at', Time.zone.now) }
+        let(:seen_at_instructeur) { now + 1.hour }
+        let(:seen_at_instructeur2) { now - 1.hour }
 
         it { is_expected.to match([]) }
         it { expect(instructeur_2.notifications_for_procedure(procedure, :en_cours)).to match([dossier]) }
@@ -305,20 +316,29 @@ describe Instructeur, type: :model do
     end
 
     context 'when there is a modification on private champs' do
-      before { dossier.champs_private.first.update_attribute('value', 'toto') }
+      before do
+        dossier.update!(last_champ_private_updated_at: now)
+        follow.update_attribute('annotations_privees_seen_at', seen_at_instructeur)
+      end
 
       it { is_expected.to match([dossier]) }
     end
 
     context 'when there is a modification on avis' do
-      before { create(:avis, dossier: dossier) }
+      before do
+        dossier.update!(last_avis_updated_at: Time.zone.now)
+        follow.update_attribute('avis_seen_at', seen_at_instructeur)
+      end
 
       it { is_expected.to match([dossier]) }
     end
 
     context 'the messagerie' do
       context 'when there is a new commentaire' do
-        before { create(:commentaire, dossier: dossier, email: 'a@b.com') }
+        before do
+          dossier.update!(last_commentaire_updated_at: Time.zone.now)
+          follow.update_attribute('messagerie_seen_at', seen_at_instructeur)
+        end
 
         it { is_expected.to match([dossier]) }
       end
@@ -339,7 +359,7 @@ describe Instructeur, type: :model do
     subject { instructeur.procedures_with_notifications(:en_cours) }
 
     context 'when there is a modification on public champs' do
-      before { dossier.champs.first.update_attribute('value', 'toto') }
+      before { dossier.update!(last_champ_updated_at: Time.zone.now) }
 
       it { is_expected.to match([procedure]) }
     end
diff --git a/spec/models/procedure_presentation_spec.rb b/spec/models/procedure_presentation_spec.rb
index 915ba52c3..6f9415bf2 100644
--- a/spec/models/procedure_presentation_spec.rb
+++ b/spec/models/procedure_presentation_spec.rb
@@ -262,7 +262,7 @@ describe ProcedurePresentation do
       let!(:older_dossier) { create(:dossier, :en_construction, procedure: procedure) }
 
       before do
-        notified_dossier.champs.first.touch(time: Time.zone.local(2018, 9, 20))
+        notified_dossier.update!(last_champ_updated_at: Time.zone.local(2018, 9, 20))
         create(:follow, instructeur: instructeur, dossier: notified_dossier, demande_seen_at: Time.zone.local(2018, 9, 10))
         notified_dossier.touch(time: Time.zone.local(2018, 9, 20))
         recent_dossier.touch(time: Time.zone.local(2018, 9, 25))