diff --git a/app/models/champs/departement_champ.rb b/app/models/champs/departement_champ.rb
index 13edb4bb4..5a99ce8ad 100644
--- a/app/models/champs/departement_champ.rb
+++ b/app/models/champs/departement_champ.rb
@@ -21,6 +21,9 @@
 #  type_de_champ_id               :integer
 #
 class Champs::DepartementChamp < Champs::TextChamp
+  validate :value_in_departement_names, unless: -> { value.nil? }
+  validate :external_id_in_departement_codes, unless: -> { external_id.nil? }
+
   def for_export
     [name, code]
   end
@@ -65,6 +68,9 @@ class Champs::DepartementChamp < Champs::TextChamp
     elsif code.blank?
       self.external_id = nil
       super(nil)
+    else
+      self.external_id = APIGeoService.departement_code(code)
+      super(code)
     end
   end
 
@@ -73,4 +79,16 @@ class Champs::DepartementChamp < Champs::TextChamp
   def formatted_value
     blank? ? "" : "#{code} – #{name}"
   end
+
+  def value_in_departement_names
+    return if value.in?(APIGeoService.departements.pluck(:name))
+
+    errors.add(:value, :not_in_departement_names)
+  end
+
+  def external_id_in_departement_codes
+    return if external_id.in?(APIGeoService.departements.pluck(:code))
+
+    errors.add(:external_id, :not_in_departement_codes)
+  end
 end
diff --git a/app/models/prefill_params.rb b/app/models/prefill_params.rb
index e4ded1975..33261a8ac 100644
--- a/app/models/prefill_params.rb
+++ b/app/models/prefill_params.rb
@@ -40,7 +40,8 @@ class PrefillParams
       TypeDeChamp.type_champs.fetch(:yes_no),
       TypeDeChamp.type_champs.fetch(:checkbox),
       TypeDeChamp.type_champs.fetch(:pays),
-      TypeDeChamp.type_champs.fetch(:regions)
+      TypeDeChamp.type_champs.fetch(:regions),
+      TypeDeChamp.type_champs.fetch(:departements)
     ]
 
     attr_reader :champ, :value
diff --git a/app/models/type_de_champ.rb b/app/models/type_de_champ.rb
index afa6a821a..05091ec70 100644
--- a/app/models/type_de_champ.rb
+++ b/app/models/type_de_champ.rb
@@ -267,7 +267,8 @@ class TypeDeChamp < ApplicationRecord
       TypeDeChamp.type_champs.fetch(:yes_no),
       TypeDeChamp.type_champs.fetch(:checkbox),
       TypeDeChamp.type_champs.fetch(:drop_down_list),
-      TypeDeChamp.type_champs.fetch(:regions)
+      TypeDeChamp.type_champs.fetch(:regions),
+      TypeDeChamp.type_champs.fetch(:departements)
     ])
   end
 
diff --git a/app/models/types_de_champ/prefill_departement_type_de_champ.rb b/app/models/types_de_champ/prefill_departement_type_de_champ.rb
new file mode 100644
index 000000000..2ec1d1d11
--- /dev/null
+++ b/app/models/types_de_champ/prefill_departement_type_de_champ.rb
@@ -0,0 +1,11 @@
+class TypesDeChamp::PrefillDepartementTypeDeChamp < TypesDeChamp::PrefillTypeDeChamp
+  def possible_values
+    departements.map { |departement| "#{departement[:code]} (#{departement[:name]})" }
+  end
+
+  private
+
+  def departements
+    @departements ||= APIGeoService.departements.sort_by { |departement| departement[:code] }
+  end
+end
diff --git a/app/models/types_de_champ/prefill_pays_type_de_champ.rb b/app/models/types_de_champ/prefill_pays_type_de_champ.rb
index 143f041e7..6e5f9952c 100644
--- a/app/models/types_de_champ/prefill_pays_type_de_champ.rb
+++ b/app/models/types_de_champ/prefill_pays_type_de_champ.rb
@@ -3,10 +3,6 @@ class TypesDeChamp::PrefillPaysTypeDeChamp < TypesDeChamp::PrefillTypeDeChamp
     countries.map { |country| "#{country[:code]} (#{country[:name]})" }
   end
 
-  def example_value
-    countries.pick(:code)
-  end
-
   private
 
   def countries
diff --git a/app/models/types_de_champ/prefill_type_de_champ.rb b/app/models/types_de_champ/prefill_type_de_champ.rb
index 296c04c48..5e9e55380 100644
--- a/app/models/types_de_champ/prefill_type_de_champ.rb
+++ b/app/models/types_de_champ/prefill_type_de_champ.rb
@@ -9,6 +9,8 @@ class TypesDeChamp::PrefillTypeDeChamp < SimpleDelegator
       TypesDeChamp::PrefillPaysTypeDeChamp.new(type_de_champ)
     when TypeDeChamp.type_champs.fetch(:regions)
       TypesDeChamp::PrefillRegionTypeDeChamp.new(type_de_champ)
+    when TypeDeChamp.type_champs.fetch(:departements)
+      TypesDeChamp::PrefillDepartementTypeDeChamp.new(type_de_champ)
     else
       new(type_de_champ)
     end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index dc8be05ec..c9f4af19e 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -130,6 +130,7 @@ en:
           yes_no_html: '"true" for Yes, "false" pour No'
           checkbox_html: '"true" to check, "false" to uncheck'
           pays_html: An <a href="https://en.wikipedia.org/wiki/ISO_3166-2" target="_blank">ISO 3166-2 country code</a>
+          departements_html: A <a href="https://fr.wikipedia.org/wiki/Num%C3%A9rotation_des_d%C3%A9partements_fran%C3%A7ais" target="_blank">department number</a>
           regions_html: An <a href="https://fr.wikipedia.org/wiki/R%C3%A9gion_fran%C3%A7aise" target="_blank">INSEE region code</a>
           date_html: ISO8601 date
           datetime_html: ISO8601 datetime
@@ -145,6 +146,7 @@ en:
           iban: FR7611315000011234567890138
           yes_no: "true"
           pays: "FR"
+          departements: "56"
           regions: "53"
           date: "2023-02-01"
           datetime: "2023-02-01T10:30"
@@ -475,6 +477,12 @@ en:
               not_in_region_names: "must be a valid region name"
             external_id:
               not_in_region_codes: "must be a valid region code"
+        "champs/departement_champ":
+          attributes:
+            value:
+              not_in_departement_names: "must be a valid department name"
+            external_id:
+              not_in_departement_codes: "must be a valid department code"
   errors:
     format: "Field « %{attribute} » %{message}"
     messages:
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index d4b864c28..b530475fc 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -121,6 +121,7 @@ fr:
           yes_no_html: '"true" pour Oui, "false" pour Non'
           checkbox_html: '"true" pour coché, "false" pour décoché'
           pays_html: Un <a href="https://en.wikipedia.org/wiki/ISO_3166-2" target="_blank">code pays ISO 3166-2</a>
+          departements_html: Un <a href="https://fr.wikipedia.org/wiki/Num%C3%A9rotation_des_d%C3%A9partements_fran%C3%A7ais" target="_blank">numéro de département</a>
           regions_html: Un <a href="https://fr.wikipedia.org/wiki/R%C3%A9gion_fran%C3%A7aise" target="_blank">code INSEE de région</a>
           datetime_html: Datetime au format ISO8601
           date_html: Date au format ISO8601
@@ -137,6 +138,7 @@ fr:
           yes_no: "true"
           civilite: "M."
           pays: "FR"
+          departements: "56"
           regions: "53"
           date: "2023-02-01"
           datetime: "2023-02-01T10:30"
@@ -470,6 +472,12 @@ fr:
               not_in_region_names: "doit être un nom de région valide"
             external_id:
               not_in_region_codes: "doit être un code de région valide"
+        "champs/departement_champ":
+          attributes:
+            value:
+              not_in_departement_names: "doit être un nom de département valide"
+            external_id:
+              not_in_departement_codes: "doit être un code de département valide"
   errors:
     format: "Le champ « %{attribute} » %{message}"
     messages:
diff --git a/spec/controllers/api/v1/dossiers_controller_spec.rb b/spec/controllers/api/v1/dossiers_controller_spec.rb
index af705addd..9c7ef5fe3 100644
--- a/spec/controllers/api/v1/dossiers_controller_spec.rb
+++ b/spec/controllers/api/v1/dossiers_controller_spec.rb
@@ -4,6 +4,13 @@ describe API::V1::DossiersController do
   let(:procedure) { create(:procedure, :with_type_de_champ, :with_type_de_champ_private, administrateur: admin) }
   let(:wrong_procedure) { create(:procedure) }
 
+  let(:memory_store) { ActiveSupport::Cache.lookup_store(:memory_store) }
+
+  before do
+    allow(Rails).to receive(:cache).and_return(memory_store)
+    Rails.cache.clear
+  end
+
   it { expect(described_class).to be < APIController }
 
   describe 'GET index (with bearer token)' do
@@ -258,7 +265,7 @@ describe API::V1::DossiersController do
             end
           end
 
-          describe 'departement' do
+          describe 'departement', vcr: { cassette_name: 'api_geo_departements' } do
             let(:procedure) { create(:procedure, :with_departement, administrateur: admin) }
             let(:dossier) { create(:dossier, :en_construction, :with_populated_champs, procedure: procedure) }
 
diff --git a/spec/controllers/api/v2/graphql_controller_spec.rb b/spec/controllers/api/v2/graphql_controller_spec.rb
index acfe61304..6f70743cd 100644
--- a/spec/controllers/api/v2/graphql_controller_spec.rb
+++ b/spec/controllers/api/v2/graphql_controller_spec.rb
@@ -42,7 +42,6 @@ describe API::V2::GraphqlController do
     allow(Rails).to receive(:cache).and_return(memory_store)
     Rails.cache.clear
 
-    allow(APIGeoService).to receive(:departement_name).with('01').and_return('Ain')
     instructeur.assign_to_procedure(procedure)
   end
 
@@ -397,7 +396,7 @@ describe API::V2::GraphqlController do
         dossier
       end
 
-      context "for individual", vcr: { cassette_name: 'api_geo_regions' } do
+      context "for individual", vcr: { cassette_name: 'api_geo_all' } do
         let(:procedure) { create(:procedure, :published, :for_individual, :with_service, :with_all_champs, :with_all_annotations, administrateurs: [admin]) }
         let(:query) do
           "{
diff --git a/spec/models/champs/departement_champ_spec.rb b/spec/models/champs/departement_champ_spec.rb
index 35353f865..1a70439d5 100644
--- a/spec/models/champs/departement_champ_spec.rb
+++ b/spec/models/champs/departement_champ_spec.rb
@@ -6,9 +6,69 @@ describe Champs::DepartementChamp, type: :model do
     Rails.cache.clear
   end
 
-  let(:champ) { described_class.new }
+  describe 'validations', vcr: { cassette_name: 'api_geo_departements' } do
+    describe 'external link' do
+      subject { build(:champ_departements, external_id: external_id) }
+
+      context 'when nil' do
+        let(:external_id) { nil }
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'when blank' do
+        let(:external_id) { '' }
+
+        it { is_expected.not_to be_valid }
+      end
+
+      context 'when included in the departement codes' do
+        let(:external_id) { "01" }
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'when not included in the departement codes' do
+        let(:external_id) { "totoro" }
+
+        it { is_expected.not_to be_valid }
+      end
+    end
+
+    describe 'value' do
+      subject { create(:champ_departements) }
+
+      before { subject.update_columns(value: value) }
+
+      context 'when nil' do
+        let(:value) { nil }
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'when blank' do
+        let(:value) { '' }
+
+        it { is_expected.not_to be_valid }
+      end
+
+      context 'when included in the departement names' do
+        let(:value) { "Ain" }
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'when not included in the departement names' do
+        let(:value) { "totoro" }
+
+        it { is_expected.not_to be_valid }
+      end
+    end
+  end
 
   describe 'value', vcr: { cassette_name: 'api_geo_departements' } do
+    let(:champ) { described_class.new }
+
     it 'with code having 2 chars' do
       champ.value = '01'
       expect(champ.external_id).to eq('01')
diff --git a/spec/models/prefill_params_spec.rb b/spec/models/prefill_params_spec.rb
index 84c99a26b..2c9ff077a 100644
--- a/spec/models/prefill_params_spec.rb
+++ b/spec/models/prefill_params_spec.rb
@@ -1,5 +1,5 @@
 RSpec.describe PrefillParams do
-  describe "#to_a", vcr: { cassette_name: 'api_geo_regions' } do
+  describe "#to_a", vcr: { cassette_name: 'api_geo_all' } do
     let(:memory_store) { ActiveSupport::Cache.lookup_store(:memory_store) }
 
     let(:procedure) { create(:procedure, :published, types_de_champ_public:, types_de_champ_private:) }
@@ -126,6 +126,7 @@ RSpec.describe PrefillParams do
     it_behaves_like "a champ public value that is authorized", :checkbox, "false"
     it_behaves_like "a champ public value that is authorized", :drop_down_list, "value"
     it_behaves_like "a champ public value that is authorized", :regions, "03"
+    it_behaves_like "a champ public value that is authorized", :departements, "03"
 
     it_behaves_like "a champ private value that is authorized", :text, "value"
     it_behaves_like "a champ private value that is authorized", :textarea, "value"
@@ -144,6 +145,7 @@ RSpec.describe PrefillParams do
     it_behaves_like "a champ private value that is authorized", :checkbox, "false"
     it_behaves_like "a champ private value that is authorized", :drop_down_list, "value"
     it_behaves_like "a champ private value that is authorized", :regions, "93"
+    it_behaves_like "a champ public value that is authorized", :departements, "03"
 
     it_behaves_like "a champ public value that is unauthorized", :decimal_number, "non decimal string"
     it_behaves_like "a champ public value that is unauthorized", :integer_number, "non integer string"
diff --git a/spec/models/type_de_champ_spec.rb b/spec/models/type_de_champ_spec.rb
index e1ca7bac6..9d891f5e1 100644
--- a/spec/models/type_de_champ_spec.rb
+++ b/spec/models/type_de_champ_spec.rb
@@ -250,6 +250,7 @@ describe TypeDeChamp do
     it_behaves_like "a prefillable type de champ", :type_de_champ_checkbox
     it_behaves_like "a prefillable type de champ", :type_de_champ_drop_down_list
     it_behaves_like "a prefillable type de champ", :type_de_champ_regions
+    it_behaves_like "a prefillable type de champ", :type_de_champ_departements
 
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_number
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_communes
@@ -267,7 +268,6 @@ describe TypeDeChamp do
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_mesri
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_carte
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_address
-    it_behaves_like "a non-prefillable type de champ", :type_de_champ_departements
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_siret
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_rna
     it_behaves_like "a non-prefillable type de champ", :type_de_champ_annuaire_education
diff --git a/spec/models/types_de_champ/prefill_departement_type_de_champ_spec.rb b/spec/models/types_de_champ/prefill_departement_type_de_champ_spec.rb
new file mode 100644
index 000000000..f43a07393
--- /dev/null
+++ b/spec/models/types_de_champ/prefill_departement_type_de_champ_spec.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+RSpec.describe TypesDeChamp::PrefillDepartementTypeDeChamp, type: :model do
+  let(:type_de_champ) { build(:type_de_champ_departements) }
+  let(:memory_store) { ActiveSupport::Cache.lookup_store(:memory_store) }
+
+  before do
+    allow(Rails).to receive(:cache).and_return(memory_store)
+    Rails.cache.clear
+  end
+
+  describe 'ancestors' do
+    subject { described_class.build(type_de_champ) }
+
+    it { is_expected.to be_kind_of(TypesDeChamp::PrefillTypeDeChamp) }
+  end
+
+  describe '#possible_values', vcr: { cassette_name: 'api_geo_departements' } do
+    let(:expected_values) {
+      APIGeoService.departements.sort_by { |departement| departement[:code] }.map { |departement| "#{departement[:code]} (#{departement[:name]})" }
+    }
+    subject(:possible_values) { described_class.new(type_de_champ).possible_values }
+
+    it { expect(possible_values).to match(expected_values) }
+  end
+end
diff --git a/spec/models/types_de_champ/prefill_pays_type_de_champ_spec.rb b/spec/models/types_de_champ/prefill_pays_type_de_champ_spec.rb
index f651d3d60..67789ba9e 100644
--- a/spec/models/types_de_champ/prefill_pays_type_de_champ_spec.rb
+++ b/spec/models/types_de_champ/prefill_pays_type_de_champ_spec.rb
@@ -2,16 +2,16 @@
 RSpec.describe TypesDeChamp::PrefillPaysTypeDeChamp, type: :model do
   let(:type_de_champ) { build(:type_de_champ_pays) }
 
+  describe 'ancestors' do
+    subject { described_class.build(type_de_champ) }
+
+    it { is_expected.to be_kind_of(TypesDeChamp::PrefillTypeDeChamp) }
+  end
+
   describe '#possible_values' do
     let(:expected_values) { APIGeoService.countries.sort_by { |country| country[:code] }.map { |country| "#{country[:code]} (#{country[:name]})" } }
     subject(:possible_values) { described_class.new(type_de_champ).possible_values }
 
     it { expect(possible_values).to match(expected_values) }
   end
-
-  describe '#example_value' do
-    subject(:example_value) { described_class.new(type_de_champ).example_value }
-
-    it { expect(example_value).to eq(APIGeoService.countries.sort_by { |country| country[:code] }.first[:code]) }
-  end
 end
diff --git a/spec/models/types_de_champ/prefill_type_de_champ_spec.rb b/spec/models/types_de_champ/prefill_type_de_champ_spec.rb
index af0e3cfc9..52508be91 100644
--- a/spec/models/types_de_champ/prefill_type_de_champ_spec.rb
+++ b/spec/models/types_de_champ/prefill_type_de_champ_spec.rb
@@ -22,6 +22,12 @@ RSpec.describe TypesDeChamp::PrefillTypeDeChamp, type: :model do
       it { expect(built).to be_kind_of(TypesDeChamp::PrefillRegionTypeDeChamp) }
     end
 
+    context 'when the type de champ is a departements' do
+      let(:type_de_champ) { build(:type_de_champ_departements) }
+
+      it { expect(built).to be_kind_of(TypesDeChamp::PrefillDepartementTypeDeChamp) }
+    end
+
     context 'when any other type de champ' do
       let(:type_de_champ) { build(:type_de_champ_date) }