diff --git a/app/models/champ.rb b/app/models/champ.rb
index c28f08d1c..89efe8f10 100644
--- a/app/models/champ.rb
+++ b/app/models/champ.rb
@@ -11,23 +11,6 @@ class Champ < ApplicationRecord
   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
@@ -64,28 +47,6 @@ class Champ < ApplicationRecord
     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 string_value
diff --git a/app/models/champs/piece_justificative_champ.rb b/app/models/champs/piece_justificative_champ.rb
index 8373686f7..2213a5579 100644
--- a/app/models/champs/piece_justificative_champ.rb
+++ b/app/models/champs/piece_justificative_champ.rb
@@ -1,10 +1,49 @@
 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