diff --git a/canaille/app/forms.py b/canaille/app/forms.py
index 6f571d08..e2b8b5e3 100644
--- a/canaille/app/forms.py
+++ b/canaille/app/forms.py
@@ -234,21 +234,6 @@ def process_formdata(self, valuelist):
         raise ValueError(self.gettext("Not a valid datetime value."))
 
 
-class ReadOnly:
-    """
-    Set a field readonly.
-    Validation fails if the form data is different than the
-    field object data, or if unset, from the field default data.
-    """
-
-    def __init__(self):
-        self.field_flags = {"readonly": True}
-
-    def __call__(self, form, field):
-        if field.data and field.object_data and field.data != field.object_data:
-            raise wtforms.ValidationError(_("This field cannot be edited"))
-
-
 def is_readonly(field):
     return field.render_kw and "readonly" in field.render_kw
 
@@ -256,9 +241,11 @@ def is_readonly(field):
 def set_readonly(field):
     field.render_kw = field.render_kw or {}
     field.render_kw["readonly"] = True
-    field.validators = list(field.validators) + [ReadOnly()]
+    field.validators = list(field.validators) + [wtforms.validators.ReadOnly()]
 
 
 def set_writable(field):
     del field.render_kw["readonly"]
-    field.validators = [v for v in field.validators if not isinstance(v, ReadOnly)]
+    field.validators = [
+        v for v in field.validators if not isinstance(v, wtforms.validators.ReadOnly)
+    ]
diff --git a/canaille/core/forms.py b/canaille/core/forms.py
index dd0afd09..bbc3c6c3 100644
--- a/canaille/core/forms.py
+++ b/canaille/core/forms.py
@@ -1,4 +1,5 @@
 import wtforms.form
+import wtforms.validators
 from canaille.app import models
 from canaille.app.forms import BaseForm
 from canaille.app.forms import DateTimeUTCField
@@ -6,7 +7,6 @@
 from canaille.app.forms import Form
 from canaille.app.forms import is_uri
 from canaille.app.forms import phone_number
-from canaille.app.forms import ReadOnly
 from canaille.app.forms import set_readonly
 from canaille.app.forms import unique_values
 from canaille.app.i18n import lazy_gettext as _
@@ -337,7 +337,7 @@ class EditGroupForm(Form):
         _("Name"),
         validators=[
             wtforms.validators.DataRequired(),
-            ReadOnly(),
+            wtforms.validators.ReadOnly(),
         ],
         render_kw={
             "readonly": "true",
@@ -400,7 +400,7 @@ class InvitationForm(Form):
 class EmailConfirmationForm(Form):
     old_emails = wtforms.FieldList(
         wtforms.EmailField(
-            validators=[ReadOnly()],
+            validators=[wtforms.validators.ReadOnly()],
             description=_(
                 "This email will be used as a recovery address to reset the password if needed"
             ),