diff --git a/app/models/champ.rb b/app/models/champ.rb
index 65f53ee9b..4daf0e05d 100644
--- a/app/models/champ.rb
+++ b/app/models/champ.rb
@@ -12,8 +12,8 @@ class Champ < ActiveRecord::Base
   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('champs.type != ?', 'ChampPrivate') }
-  scope :private_only, -> { where(type: 'ChampPrivate') }
+  scope :public_only, -> { where.not(type: 'ChampPrivate').or(where(private: [false, nil])) }
+  scope :private_only, -> { where(type: 'ChampPrivate').or(where(private: true)) }
 
   def mandatory?
     mandatory
@@ -24,7 +24,7 @@ class Champ < ActiveRecord::Base
   end
 
   def private?
-    type == 'ChampPrivate'
+    super || type == 'ChampPrivate'
   end
 
   def same_hour? num
diff --git a/app/models/type_de_champ.rb b/app/models/type_de_champ.rb
index aed2c6225..4a792d1cd 100644
--- a/app/models/type_de_champ.rb
+++ b/app/models/type_de_champ.rb
@@ -25,20 +25,12 @@ class TypeDeChamp < ActiveRecord::Base
   belongs_to :procedure
 
   has_many :champ, inverse_of: :type_de_champ, dependent: :destroy do
-    def build_params(params)
-      if proxy_association.owner.public?
-        params.merge(type: 'ChampPublic')
-      else
-        params.merge(type: 'ChampPrivate')
-      end
-    end
-
     def build(params = {})
-      super(build_params(params))
+      super(params.merge(proxy_association.owner.params_for_champ))
     end
 
     def create(params = {})
-      super(build_params(params))
+      super(params.merge(proxy_association.owner.params_for_champ))
     end
   end
   has_one :drop_down_list
@@ -50,6 +42,12 @@ class TypeDeChamp < ActiveRecord::Base
 
   before_validation :check_mandatory
 
+  def params_for_champ
+    {
+      private: private?
+    }
+  end
+
   def self.type_de_champs_list_fr
     type_champs.map { |champ| [I18n.t("activerecord.attributes.type_de_champ.type_champs.#{champ.last}"), champ.first] }
   end
diff --git a/db/migrate/20180209133452_add_private_to_champ_and_type_de_champ.rb b/db/migrate/20180209133452_add_private_to_champ_and_type_de_champ.rb
new file mode 100644
index 000000000..5feb76084
--- /dev/null
+++ b/db/migrate/20180209133452_add_private_to_champ_and_type_de_champ.rb
@@ -0,0 +1,11 @@
+class AddPrivateToChampAndTypeDeChamp < ActiveRecord::Migration[5.2]
+  disable_ddl_transaction!
+
+  def change
+    add_column :champs, :private, :boolean, index: true
+    add_column :types_de_champ, :private, :boolean, index: true
+
+    add_index :champs, :private, algorithm: :concurrently
+    add_index :types_de_champ, :private, algorithm: :concurrently
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 320d92dc2..8db9e6a21 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_02_06_153121) do
+ActiveRecord::Schema.define(version: 2018_02_09_133452) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -138,7 +138,9 @@ ActiveRecord::Schema.define(version: 2018_02_06_153121) do
     t.string "type"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.boolean "private"
     t.index ["dossier_id"], name: "index_champs_on_dossier_id"
+    t.index ["private"], name: "index_champs_on_private"
     t.index ["type_de_champ_id"], name: "index_champs_on_type_de_champ_id"
   end
 
@@ -425,6 +427,8 @@ ActiveRecord::Schema.define(version: 2018_02_06_153121) do
     t.text "description"
     t.boolean "mandatory", default: false
     t.string "type"
+    t.boolean "private"
+    t.index ["private"], name: "index_types_de_champ_on_private"
   end
 
   create_table "types_de_piece_justificative", id: :serial, force: :cascade do |t|