diff --git a/app/models/dossier.rb b/app/models/dossier.rb
index 4a3109c90..fbef6d1a3 100644
--- a/app/models/dossier.rb
+++ b/app/models/dossier.rb
@@ -233,10 +233,11 @@ class Dossier < ApplicationRecord
   scope :en_instruction,              -> { not_archived.state_en_instruction }
   scope :termine,                     -> { not_archived.state_termine }
 
-  scope :processed_in_month, -> (month) do
+  scope :processed_in_month, -> (date) do
+    date = date.to_datetime
     state_termine
       .joins(:traitements)
-      .where(traitements: { processed_at: month.beginning_of_month..month.end_of_month })
+      .where(traitements: { processed_at: date.beginning_of_month..date.end_of_month })
   end
   scope :downloadable_sorted, -> {
     state_not_brouillon
diff --git a/spec/models/dossier_spec.rb b/spec/models/dossier_spec.rb
index 4dcc91063..ce5249bc6 100644
--- a/spec/models/dossier_spec.rb
+++ b/spec/models/dossier_spec.rb
@@ -1720,4 +1720,29 @@ describe Dossier do
       expect(rebased_datetime_champ.rebased_at).not_to be_nil
     end
   end
+
+  describe '#processed_in_month' do
+    include ActiveSupport::Testing::TimeHelpers
+
+    let(:dossier_accepte_at) { DateTime.new(2022, 3, 31, 12, 0) }
+    before do
+      travel_to(dossier_accepte_at) do
+        dossier = create(:dossier, :accepte)
+      end
+    end
+
+    context 'given a date' do
+      let(:archive_date) { Date.new(2022, 3, 1) }
+      it 'includes a dossier processed_at at last day of month' do
+        expect(Dossier.processed_in_month(archive_date).count).to eq(1)
+      end
+    end
+
+    context 'given a datetime' do
+      let(:archive_date) { DateTime.new(2022, 3, 1, 12, 0) }
+      it 'includes a dossier processed_at at last day of month' do
+        expect(Dossier.processed_in_month(archive_date).count).to eq(1)
+      end
+    end
+  end
 end