diff --git a/src/authentic2_cut/custom_settings.py b/src/authentic2_cut/custom_settings.py
index 869f6db..5f31b2f 100644
--- a/src/authentic2_cut/custom_settings.py
+++ b/src/authentic2_cut/custom_settings.py
@@ -75,7 +75,6 @@ A2_FC_USER_INFO_MAPPINGS = {
     'birthcountry': {'ref': 'birthcountry', 'translation': 'insee-countries'},
     'birthplace_insee': 'birthplace',
     'birthcountry_insee': 'birthcountry',
-    'preferred_username': 'preferred_username',
     'title': {
         'ref': 'gender',
         'translation': 'simple',
@@ -84,6 +83,10 @@ A2_FC_USER_INFO_MAPPINGS = {
             'female': 'Madame',
         }
     },
+    'preferred_username': {
+        'ref': 'preferred_username',
+        'if-empty': True,
+    },
     'address': 'address.formatted',
     'phone': 'phone',
     'email': {