diff --git a/app/models/champ.rb b/app/models/champ.rb
index 91b8055c0..f396e988c 100644
--- a/app/models/champ.rb
+++ b/app/models/champ.rb
@@ -7,82 +7,21 @@ class Champ < ApplicationRecord
 
   delegate :libelle, :type_champ, :order_place, :mandatory?, :description, :drop_down_list, to: :type_de_champ
 
-  before_save :format_date_to_iso, if: Proc.new { type_champ == 'date' }
-  before_save :format_datetime, if: Proc.new { type_champ == 'datetime' }
-  before_save :multiple_select_to_string, if: Proc.new { type_champ == 'multiple_drop_down_list' }
-
   scope :updated_since?, -> (date) { where('champs.updated_at > ?', date) }
   scope :public_only, -> { where(private: false) }
   scope :private_only, -> { where(private: true) }
 
-  PIECE_JUSTIFICATIVE_FILE_MAX_SIZE = 200.megabytes
-
-  PIECE_JUSTIFICATIVE_FILE_ACCEPTED_FORMATS = [
-    "application/pdf",
-    "application/msword",
-    "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
-    "application/vnd.ms-excel",
-    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
-    "application/vnd.ms-powerpoint",
-    "application/vnd.openxmlformats-officedocument.presentationml.presentation",
-    "application/vnd.oasis.opendocument.text",
-    "application/vnd.oasis.opendocument.presentation",
-    "application/vnd.oasis.opendocument.spreadsheet",
-    "image/png",
-    "image/jpeg"
-  ]
-
   def public?
     !private?
   end
 
-  def same_hour?(num)
-    same_date? num, '%H'
-  end
-
-  def same_minute?(num)
-    same_date? num, '%M'
-  end
-
   def mandatory_and_blank?
-    if type_champ == 'piece_justificative'
-      mandatory? && !piece_justificative_file.attached?
-    else
-      mandatory? && value.blank?
-    end
-  end
-
-  def same_date?(num, compare)
-    if type_champ == 'datetime' && value.present?
-      if value.to_datetime.strftime(compare) == num
-        return true
-      end
-    end
-    false
-  end
-
-  def self.regions
-    JSON.parse(Carto::GeoAPI::Driver.regions).sort_by { |e| e['nom'] }.pluck("nom")
-  end
-
-  def self.departements
-    JSON.parse(Carto::GeoAPI::Driver.departements).map { |liste| "#{liste['code']} - #{liste['nom']}" }.push('99 - Étranger')
-  end
-
-  def self.pays
-    JSON.parse(Carto::GeoAPI::Driver.pays).pluck("nom")
+    mandatory? && value.blank?
   end
 
   def to_s
     if value.present?
-      case type_champ
-      when 'date'
-        Date.parse(value).strftime('%d/%m/%Y')
-      when 'multiple_drop_down_list'
-        drop_down_list.selected_options_without_decorator(self).join(', ')
-      else
-        value.to_s
-      end
+      string_value
     else
       ''
     end
@@ -90,80 +29,19 @@ class Champ < ApplicationRecord
 
   def for_export
     if value.present?
-      case type_champ
-      when 'textarea'
-        ActionView::Base.full_sanitizer.sanitize(value)
-      when 'yes_no'
-        value == 'true' ? 'oui' : 'non'
-      when 'multiple_drop_down_list'
-        drop_down_list.selected_options_without_decorator(self).join(', ')
-      else
-        value
-      end
+      value_for_export
     else
       nil
     end
   end
 
-  def piece_justificative_file_errors
-    errors = []
-
-    if piece_justificative_file.attached? && piece_justificative_file.previous_changes.present?
-      if piece_justificative_file.blob.byte_size > PIECE_JUSTIFICATIVE_FILE_MAX_SIZE
-        errors << "Le fichier #{piece_justificative_file.filename.to_s} est trop lourd, il doit faire au plus #{PIECE_JUSTIFICATIVE_FILE_MAX_SIZE.to_s(:human_size, precision: 2)}"
-      end
-
-      if !piece_justificative_file.blob.content_type.in?(PIECE_JUSTIFICATIVE_FILE_ACCEPTED_FORMATS)
-        errors << "Le fichier #{piece_justificative_file.filename.to_s} est dans un format que nous n'acceptons pas"
-      end
-
-      # FIXME: add Clamav check
-    end
-
-    if errors.present?
-      piece_justificative_file.purge
-    end
-
-    errors
-  end
-
   private
 
-  def format_date_to_iso
-    date = begin
-      Date.parse(value).iso8601
-    rescue
-      nil
-    end
-    self.value = date
+  def string_value
+    value.to_s
   end
 
-  def format_datetime
-    if (value =~ /=>/).present?
-      date = begin
-        hash_date = YAML.safe_load(value.gsub('=>', ': '))
-        year, month, day, hour, minute = hash_date.values_at(1,2,3,4,5)
-        DateTime.new(year, month, day, hour, minute).strftime("%d/%m/%Y %H:%M")
-      rescue
-        nil
-      end
-      self.value = date
-    elsif /^\d{2}\/\d{2}\/\d{4}\s\d{2}:\d{2}$/.match?(value) # old browsers can send with dd/mm/yyyy hh:mm format
-      self.value = DateTime.parse(value, "%d/%m/%Y %H:%M").strftime("%Y-%m-%d %H:%M")
-    elsif !(/^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}$/.match?(value)) # a datetime not correctly formatted should not be stored
-      self.value = nil
-    end
-  end
-
-  def multiple_select_to_string
-    if value.present?
-      json = JSON.parse(value)
-      if json == ['']
-        self.value = nil
-      else
-        json = json - ['']
-        self.value = json.to_s
-      end
-    end
+  def value_for_export
+    value
   end
 end
diff --git a/app/models/champs/date_champ.rb b/app/models/champs/date_champ.rb
index 7b391c5e9..310f608a9 100644
--- a/app/models/champs/date_champ.rb
+++ b/app/models/champs/date_champ.rb
@@ -1,2 +1,18 @@
 class Champs::DateChamp < Champ
+  before_save :format_before_save
+
+  private
+
+  def format_before_save
+    self.value =
+      begin
+        Date.parse(value).iso8601
+      rescue
+        nil
+      end
+  end
+
+  def string_value
+    Date.parse(value).strftime('%d/%m/%Y')
+  end
 end
diff --git a/app/models/champs/datetime_champ.rb b/app/models/champs/datetime_champ.rb
index 8b5c9c73f..1388ccc1f 100644
--- a/app/models/champs/datetime_champ.rb
+++ b/app/models/champs/datetime_champ.rb
@@ -1,2 +1,34 @@
 class Champs::DatetimeChamp < Champ
+  before_save :format_before_save
+
+  def same_hour?(num)
+    same_date?(num, '%H')
+  end
+
+  def same_minute?(num)
+    same_date?(num, '%M')
+  end
+
+  private
+
+  def same_date?(num, compare)
+    return value.present? && value.to_datetime.strftime(compare) == num
+  end
+
+  def format_before_save
+    if (value =~ /=>/).present?
+      self.value =
+        begin
+          hash_date = YAML.safe_load(value.gsub('=>', ': '))
+          year, month, day, hour, minute = hash_date.values_at(1,2,3,4,5)
+          DateTime.new(year, month, day, hour, minute).strftime("%d/%m/%Y %H:%M")
+        rescue
+          nil
+        end
+    elsif /^\d{2}\/\d{2}\/\d{4}\s\d{2}:\d{2}$/.match?(value) # old browsers can send with dd/mm/yyyy hh:mm format
+      self.value = DateTime.parse(value, "%d/%m/%Y %H:%M").strftime("%Y-%m-%d %H:%M")
+    elsif !(/^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}$/.match?(value)) # a datetime not correctly formatted should not be stored
+      self.value = nil
+    end
+  end
 end
diff --git a/app/models/champs/departement_champ.rb b/app/models/champs/departement_champ.rb
index ee9803389..0cb4a8e68 100644
--- a/app/models/champs/departement_champ.rb
+++ b/app/models/champs/departement_champ.rb
@@ -1,2 +1,5 @@
 class Champs::DepartementChamp < Champs::TextChamp
+  def self.departements
+    JSON.parse(Carto::GeoAPI::Driver.departements).map { |liste| "#{liste['code']} - #{liste['nom']}" }.push('99 - Étranger')
+  end
 end
diff --git a/app/models/champs/multiple_drop_down_list_champ.rb b/app/models/champs/multiple_drop_down_list_champ.rb
index 5182673b5..b0ca0e121 100644
--- a/app/models/champs/multiple_drop_down_list_champ.rb
+++ b/app/models/champs/multiple_drop_down_list_champ.rb
@@ -1,2 +1,25 @@
 class Champs::MultipleDropDownListChamp < Champ
+  before_save :format_before_save
+
+  private
+
+  def format_before_save
+    if value.present?
+      json = JSON.parse(value)
+      if json == ['']
+        self.value = nil
+      else
+        json = json - ['']
+        self.value = json.to_s
+      end
+    end
+  end
+
+  def string_value
+    drop_down_list.selected_options_without_decorator(self).join(', ')
+  end
+
+  def value_for_export
+    drop_down_list.selected_options_without_decorator(self).join(', ')
+  end
 end
diff --git a/app/models/champs/pays_champ.rb b/app/models/champs/pays_champ.rb
index 95b89893f..f8204f4d0 100644
--- a/app/models/champs/pays_champ.rb
+++ b/app/models/champs/pays_champ.rb
@@ -1,2 +1,5 @@
 class Champs::PaysChamp < Champs::TextChamp
+  def self.pays
+    JSON.parse(Carto::GeoAPI::Driver.pays).pluck("nom")
+  end
 end
diff --git a/app/models/champs/piece_justificative_champ.rb b/app/models/champs/piece_justificative_champ.rb
index 4c4270609..2213a5579 100644
--- a/app/models/champs/piece_justificative_champ.rb
+++ b/app/models/champs/piece_justificative_champ.rb
@@ -1,6 +1,51 @@
 class Champs::PieceJustificativeChamp < Champ
   after_commit :create_virus_scan
 
+  PIECE_JUSTIFICATIVE_FILE_MAX_SIZE = 200.megabytes
+
+  PIECE_JUSTIFICATIVE_FILE_ACCEPTED_FORMATS = [
+    "application/pdf",
+    "application/msword",
+    "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+    "application/vnd.ms-excel",
+    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+    "application/vnd.ms-powerpoint",
+    "application/vnd.openxmlformats-officedocument.presentationml.presentation",
+    "application/vnd.oasis.opendocument.text",
+    "application/vnd.oasis.opendocument.presentation",
+    "application/vnd.oasis.opendocument.spreadsheet",
+    "image/png",
+    "image/jpeg"
+  ]
+
+  def mandatory_and_blank?
+    mandatory? && !piece_justificative_file.attached?
+  end
+
+  def piece_justificative_file_errors
+    errors = []
+
+    if piece_justificative_file.attached? && piece_justificative_file.previous_changes.present?
+      if piece_justificative_file.blob.byte_size > PIECE_JUSTIFICATIVE_FILE_MAX_SIZE
+        errors << "Le fichier #{piece_justificative_file.filename.to_s} est trop lourd, il doit faire au plus #{PIECE_JUSTIFICATIVE_FILE_MAX_SIZE.to_s(:human_size, precision: 2)}"
+      end
+
+      if !piece_justificative_file.blob.content_type.in?(PIECE_JUSTIFICATIVE_FILE_ACCEPTED_FORMATS)
+        errors << "Le fichier #{piece_justificative_file.filename.to_s} est dans un format que nous n'acceptons pas"
+      end
+
+      # FIXME: add Clamav check
+    end
+
+    if errors.present?
+      piece_justificative_file.purge
+    end
+
+    errors
+  end
+
+  private
+
   def create_virus_scan
     if self.piece_justificative_file&.attachment&.blob.present?
       VirusScan.where(champ: self).where.not(blob_key: self.piece_justificative_file.blob.key).delete_all
diff --git a/app/models/champs/region_champ.rb b/app/models/champs/region_champ.rb
index ba9045087..8c5320c29 100644
--- a/app/models/champs/region_champ.rb
+++ b/app/models/champs/region_champ.rb
@@ -1,2 +1,5 @@
 class Champs::RegionChamp < Champs::TextChamp
+  def self.regions
+    JSON.parse(Carto::GeoAPI::Driver.regions).sort_by { |e| e['nom'] }.pluck("nom")
+  end
 end
diff --git a/app/models/champs/textarea_champ.rb b/app/models/champs/textarea_champ.rb
index eedaac8b1..58e8d2db2 100644
--- a/app/models/champs/textarea_champ.rb
+++ b/app/models/champs/textarea_champ.rb
@@ -1,2 +1,7 @@
 class Champs::TextareaChamp < Champs::TextChamp
+  private
+
+  def value_for_export
+    ActionView::Base.full_sanitizer.sanitize(value)
+  end
 end
diff --git a/app/models/champs/yes_no_champ.rb b/app/models/champs/yes_no_champ.rb
index 6653a50d4..a73777fa8 100644
--- a/app/models/champs/yes_no_champ.rb
+++ b/app/models/champs/yes_no_champ.rb
@@ -1,2 +1,7 @@
 class Champs::YesNoChamp < Champs::CheckboxChamp
+  private
+
+  def value_for_export
+    value == 'true' ? 'oui' : 'non'
+  end
 end
diff --git a/app/views/shared/dossiers/editable_champs/_departements.html.haml b/app/views/shared/dossiers/editable_champs/_departements.html.haml
index 90c2ca408..9f7cc8a8b 100644
--- a/app/views/shared/dossiers/editable_champs/_departements.html.haml
+++ b/app/views/shared/dossiers/editable_champs/_departements.html.haml
@@ -1,3 +1,3 @@
 = form.select :value,
-  Champ.departements,
+  Champs::DepartementChamp.departements,
   required: champ.mandatory?
diff --git a/app/views/shared/dossiers/editable_champs/_pays.html.haml b/app/views/shared/dossiers/editable_champs/_pays.html.haml
index cdc2e489d..aba08f38a 100644
--- a/app/views/shared/dossiers/editable_champs/_pays.html.haml
+++ b/app/views/shared/dossiers/editable_champs/_pays.html.haml
@@ -1,3 +1,3 @@
 = form.select :value,
-  Champ.pays,
+  Champs::PaysChamp.pays,
   required: champ.mandatory?
diff --git a/app/views/shared/dossiers/editable_champs/_regions.html.haml b/app/views/shared/dossiers/editable_champs/_regions.html.haml
index b947a8d31..460a4b1af 100644
--- a/app/views/shared/dossiers/editable_champs/_regions.html.haml
+++ b/app/views/shared/dossiers/editable_champs/_regions.html.haml
@@ -1,3 +1,3 @@
 = form.select :value,
-  Champ.regions,
+  Champs::RegionChamp.regions,
   required: champ.mandatory?
diff --git a/app/views/users/description/champs/_departements.html.haml b/app/views/users/description/champs/_departements.html.haml
index 5fd949ccd..6fb027390 100644
--- a/app/views/users/description/champs/_departements.html.haml
+++ b/app/views/users/description/champs/_departements.html.haml
@@ -1,2 +1,2 @@
 = select_tag("champs['#{champ.id}']",
-  options_for_select(Champ.departements, selected: champ.object.value))
+  options_for_select(Champs::DepartementChamp.departements, selected: champ.object.value))
diff --git a/app/views/users/description/champs/_pays.html.haml b/app/views/users/description/champs/_pays.html.haml
index 2f530b683..67981205c 100644
--- a/app/views/users/description/champs/_pays.html.haml
+++ b/app/views/users/description/champs/_pays.html.haml
@@ -1,2 +1,2 @@
 = select_tag("champs['#{champ.id}']",
-  options_for_select(Champ.pays, selected: champ.object.value))
+  options_for_select(Champs::PaysChamp.pays, selected: champ.object.value))
diff --git a/app/views/users/description/champs/_regions.html.haml b/app/views/users/description/champs/_regions.html.haml
index 613b6af27..24c6f4bc5 100644
--- a/app/views/users/description/champs/_regions.html.haml
+++ b/app/views/users/description/champs/_regions.html.haml
@@ -1,2 +1,2 @@
 = select_tag("champs['#{champ.id}']",
-  options_for_select(Champ.regions, selected: champ.object.value))
+  options_for_select(Champs::RegionChamp.regions, selected: champ.object.value))
diff --git a/spec/features/new_user/dossier_spec.rb b/spec/features/new_user/dossier_spec.rb
index 763b9555e..b9145ab37 100644
--- a/spec/features/new_user/dossier_spec.rb
+++ b/spec/features/new_user/dossier_spec.rb
@@ -12,8 +12,8 @@ feature 'The user' do
   # there are no extraneous input
   # attached file works
   scenario 'fill a dossier', js: true do
-    allow(Champ).to receive(:regions).and_return(['region1', 'region2']).at_least(:once)
-    allow(Champ).to receive(:departements).and_return(['dep1', 'dep2']).at_least(:once)
+    allow(Champs::RegionChamp).to receive(:regions).and_return(['region1', 'region2']).at_least(:once)
+    allow(Champs::DepartementChamp).to receive(:departements).and_return(['dep1', 'dep2']).at_least(:once)
 
     log_in(user.email, password, procedure)
 
diff --git a/spec/models/champ_shared_example.rb b/spec/models/champ_shared_example.rb
index a424fc824..24d150196 100644
--- a/spec/models/champ_shared_example.rb
+++ b/spec/models/champ_shared_example.rb
@@ -27,7 +27,7 @@ shared_examples 'champ_spec' do
   end
 
   describe '.departement', vcr: { cassette_name: 'call_geo_api_departements' } do
-    subject { Champ.departements }
+    subject { Champs::DepartementChamp.departements }
 
     it { expect(subject).to include '99 - Étranger' }
   end