diff --git a/avisstage/documents.py b/avisstage/documents.py
index 3995b3c..b2fcf50 100644
--- a/avisstage/documents.py
+++ b/avisstage/documents.py
@@ -46,27 +46,30 @@ class StageDocument(DocType):
         ]
 
     def prepare_thematiques(self, instance):
-        return ", ".join(instance.thematiques.all().values_list("name", flat=True))
+        return ", ".join(instance.thematiques.all().values_list("name", flat=True)).lower()
 
     def prepare_matieres(self, instance):
-        return ", ".join(instance.matieres.all().values_list("nom", flat=True))
+        return ", ".join(instance.matieres.all().values_list("nom", flat=True)).lower()
 
     def prepare_niveau_scol(self, instance):
-        return instance.get_niveau_scol_display()
+        return instance.get_niveau_scol_display().lower()
 
     def prepare_type_stage(self, instance):
-        return instance.type_stage_fancy
+        return instance.type_stage_fancy.lower()
 
     def prepare_date_fin(self, instance):
         return instance.date_fin.year
 
     def prepare_date_debut(self, instance):
         return instance.date_debut.year
+
+    def prepare_sujet(self, instance):
+        return instance.sujet.lower()
     
     # Hook pour l'affichage des noms de pays
     def prepare(self, instance):
         data = super(StageDocument, self).prepare(instance)
         
         for lieu in data['lieux']:
-            lieu['pays'] = PAYS_DICT[lieu['pays']]
+            lieu['pays'] = PAYS_DICT[lieu['pays']].lower()
         return data