diff --git a/canaille/backends/ldap/ldapobject.py b/canaille/backends/ldap/ldapobject.py
index c52fbf00..79ce1af0 100644
--- a/canaille/backends/ldap/ldapobject.py
+++ b/canaille/backends/ldap/ldapobject.py
@@ -181,10 +181,6 @@ def __setattr__(self, name, value):
         ldap_name = self.python_attribute_to_ldap(name)
         self.set_ldap_attribute(ldap_name, value)
 
-    def __delattr__(self, name):
-        ldap_name = self.python_attribute_to_ldap(name)
-        self.delete_ldap_attribute(ldap_name)
-
     def has_ldap_attribute(self, name):
         return name in self.ldap_object_attributes() and (
             name in self.changes or name in self.state
@@ -213,9 +209,6 @@ def set_ldap_attribute(self, name, value):
         value = listify(value)
         self.changes[name] = value
 
-    def delete_ldap_attribute(self, name):
-        self.changes[name] = [None]
-
     @property
     def rdn_value(self):
         value = self.get_ldap_attribute(self.rdn_attribute)
diff --git a/canaille/backends/memory/models.py b/canaille/backends/memory/models.py
index a05edc5e..19fd1125 100644
--- a/canaille/backends/memory/models.py
+++ b/canaille/backends/memory/models.py
@@ -208,17 +208,6 @@ def __setattr__(self, name, value):
         else:
             super().__setattr__(name, value)
 
-    def __delattr__(self, name):
-        try:
-            del self.state[name]
-        except KeyError:
-            pass
-
-        try:
-            del self.cache[name]
-        except KeyError:
-            pass
-
     @property
     def identifier(self):
         return getattr(self, self.identifier_attribute)
diff --git a/canaille/core/account.py b/canaille/core/account.py
index d0268360..83e05a59 100644
--- a/canaille/core/account.py
+++ b/canaille/core/account.py
@@ -447,7 +447,7 @@ def profile_create(current_app, form):
             setattr(user, attribute.name, data)
 
         if "photo" in form and form["photo_delete"].data:
-            del user.photo
+            user.photo = None
 
     given_name = user.given_name if user.given_name else ""
     family_name = user.family_name if user.family_name else ""
@@ -522,7 +522,7 @@ def profile_edition_main_form_validation(user, edited_user, profile_form):
             setattr(edited_user, attribute.name, data)
 
     if "photo" in profile_form and profile_form["photo_delete"].data:
-        del edited_user.photo
+        edited_user.photo = None
 
     if "preferred_language" in request.form:
         # Refresh the babel cache in case the lang is updated
@@ -731,7 +731,7 @@ def profile_settings(user, edited_user):
         and edited_user.locked
     ):
         flash(_("The account has been unlocked"), "success")
-        del edited_user.lock_date
+        edited_user.lock_date = None
         edited_user.save()
 
         return profile_settings_edit(user, edited_user)
diff --git a/tests/core/test_account.py b/tests/core/test_account.py
index abb34e6e..e51119a5 100644
--- a/tests/core/test_account.py
+++ b/tests/core/test_account.py
@@ -217,7 +217,7 @@ def test_user_password_deleted_during_login(testclient, backend):
     res = res.form.submit().follow()
     res.form["password"] = "correct horse battery staple"
 
-    del u.password
+    u.password = None
     u.save()
 
     res = res.form.submit(status=302)
@@ -362,7 +362,7 @@ def test_account_locking(user, backend):
         "Your account has been locked.",
     )
 
-    del user.lock_date
+    user.lock_date = None
     user.save()
     assert not user.locked
     assert not models.User.get(id=user.id).locked
@@ -416,7 +416,7 @@ def test_signin_locked_account(testclient, user):
     res = res.form.submit()
     res.mustcontain("Your account has been locked.")
 
-    del user.lock_date
+    user.lock_date = None
     user.save()