diff --git a/lib/tasks/deployment/20230130094747_normalize_regions.rake b/lib/tasks/deployment/20230130094747_normalize_regions.rake
new file mode 100644
index 000000000..fd6d4a9f6
--- /dev/null
+++ b/lib/tasks/deployment/20230130094747_normalize_regions.rake
@@ -0,0 +1,45 @@
+namespace :after_party do
+  desc 'Deployment task: normalize_regions'
+  task normalize_regions: :environment do
+    puts "Running deploy task 'normalize_regions'"
+
+    scope_external_id_blank_value_blank = Champs::RegionChamp.where(external_id: [nil, ''], value: [nil, ''])
+    scope_value_blank = Champs::RegionChamp.where(value: [nil, '']).where.not(external_id: [nil, ''])
+    scope_external_id_blank = Champs::RegionChamp.where(external_id: [nil, '']).where.not(value: [nil, ''])
+    scope_provence = Champs::RegionChamp.where(value: "Provence-Alpes-Côte d'Azur")
+
+    progress = ProgressReport.new(
+      scope_external_id_blank_value_blank.count +
+      scope_value_blank.count +
+      scope_external_id_blank.count +
+      scope_provence.count
+    )
+
+    scope_external_id_blank_value_blank.in_batches(of: 10_000) do |regions|
+      progress.inc(regions.count)
+      regions.update_all(external_id: nil, value: nil)
+    end
+
+    scope_value_blank.find_each do |champ|
+      champ.update_columns(value: APIGeoService.region_name(champ.external_id))
+      progress.inc
+    end
+
+    scope_external_id_blank.find_each do |champ|
+      champ.update_columns(external_id: APIGeoService.region_code(champ.value))
+      progress.inc
+    end
+
+    scope_provence.in_batches(of: 10_000) do |regions|
+      progress.inc(regions.count)
+      regions.update_all(external_id: "93", value: "Provence-Alpes-Côte d’Azur")
+    end
+
+    progress.finish
+
+    # Update task as completed.  If you remove the line below, the task will
+    # run with every deploy (or every time you call after_party:run).
+    AfterParty::TaskRecord
+      .create version: AfterParty::TaskRecorder.new(__FILE__).timestamp
+  end
+end
diff --git a/spec/lib/tasks/deployment/20230130094747_normalize_regions_spec.rake b/spec/lib/tasks/deployment/20230130094747_normalize_regions_spec.rake
new file mode 100644
index 000000000..c7a5bdeba
--- /dev/null
+++ b/spec/lib/tasks/deployment/20230130094747_normalize_regions_spec.rake
@@ -0,0 +1,139 @@
+describe '20230130094747_normalize_regions', vcr: { cassette_name: 'api_geo_regions' } do
+  let(:champ) { create(:champ_regions) }
+  let(:rake_task) { Rake::Task['after_party:normalize_regions'] }
+  let(:memory_store) { ActiveSupport::Cache.lookup_store(:memory_store) }
+
+  subject(:run_task) { rake_task.invoke }
+
+  before do
+    allow(Rails).to receive(:cache).and_return(memory_store)
+    Rails.cache.clear
+  end
+
+  after { rake_task.reenable }
+
+  shared_examples "a non-changer" do |external_id, value|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.not_to change { champ.reload.external_id } }
+
+    it { expect { run_task }.not_to change { champ.reload.value } }
+  end
+
+  shared_examples "an external_id nullifier" do |external_id, value|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.to change { champ.reload.external_id }.from(external_id).to(nil) }
+
+    it { expect { run_task }.not_to change { champ.reload.value } }
+  end
+
+  shared_examples "a value nullifier" do |external_id, value|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.not_to change { champ.reload.external_id } }
+
+    it { expect { run_task }.to change { champ.reload.value }.from(value).to(nil) }
+  end
+
+  shared_examples "an external_id and value nullifier" do |external_id, value|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.to change { champ.reload.external_id }.from(external_id).to(nil) }
+
+    it { expect { run_task }.to change { champ.reload.value }.from(value).to(nil) }
+  end
+
+  shared_examples "an external_id updater" do |external_id, value, expected_external_id|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.to change { champ.reload.external_id }.from(external_id).to(expected_external_id) }
+
+    it { expect { run_task }.not_to change { champ.reload.value } }
+  end
+
+  shared_examples "a result checker" do |external_id, value, expected_external_id, expected_value|
+    before do
+      champ.update_columns(external_id:, value:)
+      run_task
+    end
+
+    it { expect(champ.reload.external_id).to eq(expected_external_id) }
+
+    it { expect(champ.reload.value).to eq(expected_value) }
+  end
+
+  shared_examples "a value updater" do |external_id, value, expected_value|
+    before { champ.update_columns(external_id:, value:) }
+
+    it { expect { run_task }.not_to change { champ.reload.external_id } }
+
+    it { expect { run_task }.to change { champ.reload.value }.from(value).to(expected_value) }
+  end
+
+  it_behaves_like "a non-changer", nil, nil
+  it_behaves_like "an external_id nullifier", '', nil
+  it_behaves_like "a value nullifier", nil, ''
+  it_behaves_like "an external_id and value nullifier", '', ''
+  it_behaves_like "an external_id updater", nil, 'Auvergne-Rhône-Alpes', '84'
+  it_behaves_like "an external_id updater", '', 'Auvergne-Rhône-Alpes', '84'
+  it_behaves_like "a value updater", '11', nil, 'Île-de-France'
+
+  # Integrity data check:
+  it_behaves_like "a result checker", "84", "Auvergne-Rhône-Alpes", "84", "Auvergne-Rhône-Alpes"
+  it_behaves_like "a result checker", nil, "Auvergne-Rhône-Alpes", "84", "Auvergne-Rhône-Alpes"
+  it_behaves_like "a result checker", '', "Auvergne-Rhône-Alpes", "84", "Auvergne-Rhône-Alpes"
+  it_behaves_like "a result checker", "27", "Bourgogne-Franche-Comté", "27", "Bourgogne-Franche-Comté"
+  it_behaves_like "a result checker", nil, "Bourgogne-Franche-Comté", "27", "Bourgogne-Franche-Comté"
+  it_behaves_like "a result checker", '', "Bourgogne-Franche-Comté", "27", "Bourgogne-Franche-Comté"
+  it_behaves_like "a result checker", "53", "Bretagne", "53", "Bretagne"
+  it_behaves_like "a result checker", nil, "Bretagne", "53", "Bretagne"
+  it_behaves_like "a result checker", '', "Bretagne", "53", "Bretagne"
+  it_behaves_like "a result checker", "24", "Centre-Val de Loire", "24", "Centre-Val de Loire"
+  it_behaves_like "a result checker", nil, "Centre-Val de Loire", "24", "Centre-Val de Loire"
+  it_behaves_like "a result checker", '', "Centre-Val de Loire", "24", "Centre-Val de Loire"
+  it_behaves_like "a result checker", "94", "Corse", "94", "Corse"
+  it_behaves_like "a result checker", nil, "Corse", "94", "Corse"
+  it_behaves_like "a result checker", '', "Corse", "94", "Corse"
+  it_behaves_like "a result checker", "44", "Grand Est", "44", "Grand Est"
+  it_behaves_like "a result checker", nil, "Grand Est", "44", "Grand Est"
+  it_behaves_like "a result checker", '', "Grand Est", "44", "Grand Est"
+  it_behaves_like "a result checker", "01", "Guadeloupe", "01", "Guadeloupe"
+  it_behaves_like "a result checker", nil, "Guadeloupe", "01", "Guadeloupe"
+  it_behaves_like "a result checker", '', "Guadeloupe", "01", "Guadeloupe"
+  it_behaves_like "a result checker", "03", "Guyane", "03", "Guyane"
+  it_behaves_like "a result checker", nil, "Guyane", "03", "Guyane"
+  it_behaves_like "a result checker", '', "Guyane", "03", "Guyane"
+  it_behaves_like "a result checker", "32", "Hauts-de-France", "32", "Hauts-de-France"
+  it_behaves_like "a result checker", nil, "Hauts-de-France", "32", "Hauts-de-France"
+  it_behaves_like "a result checker", '', "Hauts-de-France", "32", "Hauts-de-France"
+  it_behaves_like "a result checker", "04", "La Réunion", "04", "La Réunion"
+  it_behaves_like "a result checker", nil, "La Réunion", "04", "La Réunion"
+  it_behaves_like "a result checker", '', "La Réunion", "04", "La Réunion"
+  it_behaves_like "a result checker", "02", "Martinique", "02", "Martinique"
+  it_behaves_like "a result checker", nil, "Martinique", "02", "Martinique"
+  it_behaves_like "a result checker", '', "Martinique", "02", "Martinique"
+  it_behaves_like "a result checker", "06", "Mayotte", "06", "Mayotte"
+  it_behaves_like "a result checker", nil, "Mayotte", "06", "Mayotte"
+  it_behaves_like "a result checker", '', "Mayotte", "06", "Mayotte"
+  it_behaves_like "a result checker", "28", "Normandie", "28", "Normandie"
+  it_behaves_like "a result checker", nil, "Normandie", "28", "Normandie"
+  it_behaves_like "a result checker", '', "Normandie", "28", "Normandie"
+  it_behaves_like "a result checker", "75", "Nouvelle-Aquitaine", "75", "Nouvelle-Aquitaine"
+  it_behaves_like "a result checker", nil, "Nouvelle-Aquitaine", "75", "Nouvelle-Aquitaine"
+  it_behaves_like "a result checker", '', "Nouvelle-Aquitaine", "75", "Nouvelle-Aquitaine"
+  it_behaves_like "a result checker", "76", "Occitanie", "76", "Occitanie"
+  it_behaves_like "a result checker", nil, "Occitanie", "76", "Occitanie"
+  it_behaves_like "a result checker", '', "Occitanie", "76", "Occitanie"
+  it_behaves_like "a result checker", "52", "Pays de la Loire", "52", "Pays de la Loire"
+  it_behaves_like "a result checker", nil, "Pays de la Loire", "52", "Pays de la Loire"
+  it_behaves_like "a result checker", '', "Pays de la Loire", "52", "Pays de la Loire"
+  it_behaves_like "a result checker", "93", "Provence-Alpes-Côte d'Azur", "93", "Provence-Alpes-Côte d’Azur"
+  it_behaves_like "a result checker", nil, "Provence-Alpes-Côte d'Azur", "93", "Provence-Alpes-Côte d’Azur"
+  it_behaves_like "a result checker", '', "Provence-Alpes-Côte d'Azur", "93", "Provence-Alpes-Côte d’Azur"
+  it_behaves_like "a result checker", "93", "Provence-Alpes-Côte d’Azur", "93", "Provence-Alpes-Côte d’Azur"
+  it_behaves_like "a result checker", "11", "Île-de-France", "11", "Île-de-France"
+  it_behaves_like "a result checker", "11", nil, "11", "Île-de-France"
+  it_behaves_like "a result checker", nil, "Île-de-France", "11", "Île-de-France"
+  it_behaves_like "a result checker", '', "Île-de-France", "11", "Île-de-France"
+end