Bind UniqueConstraint error message to a field

Using Django Forms & APIs
1

Hi,
how can I display only the UniqueConstraint error next to the field? Do I have to override the save method?
grafik

In my manage.py, I created a Model with a UniqueConstraint

class User(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField(
        _("email address"), 
        unique=True,
        # Previos normal errormesage displayed along side the input
        # error_messages={
        #     "unique": _("A user with this email address already exists."),
        # },
    )

    # ...

    class Meta:
        constraints = [
            UniqueConstraint(
                Lower("email"),
                name="user_email_ci_uniqueness",
            ),
        ]

using this template:
signupForm.html:

<form id="form" method="post" enctype="multipart/form-data">
    {% csrf_token %}
    {{ form }}
    <input type="submit" value="Sign up">
</form>
addtional infos (urls.py, views.py, forms.py):

urls.py:

urlpatterns = [
    path("signup/", 
         views.SignupView.as_view(), 
         name="sign_up"),
]

views.py:

class SignupView(CreateView):
    form_class = SignupForm
    model = User
    template_name = "users/signupForm.html"
    success_url = "/"

forms.py:

class SignupForm(UserCreationForm):
    class Meta(UserCreationForm.Meta):
        model = User
        fields = ("email",)

I’m using Django 4.2 and I couldn’t find anything on this.
Thank you

2

For anyone with the same question. This helped me a lot:

Especially this part:

class RegisterForm(UserCreationForm):
email = forms.EmailField(required=True)
def clean_email(self):
    email = self.cleaned_data['email']
    if User.objects.filter(email__iexact=email).exists():
        raise forms.ValidationError(_("The given email is already registered."))
    return email

Have a good day