__init__() got an unexpected keyword argument 'user'

LivingRoom.objects.create() calls LivingRoom.__init__() - as you might have noticed if you had read the traceback - passing it the same arguments. To make a long story short, a Django models.Model subclass's initializer is best left alone, or should accept *args and **kwargs matching the model's meta fields. The correct way to provide default values for fields is in the field constructor using the default keyword as explained in the FineManual.

You can't do

LivingRoom.objects.create(user=instance)

because you have an __init__ method that does NOT take user as argument.

You need something like

#signal function: if a user is created, add control livingroom to the user    
def create_control_livingroom(sender, instance, created, **kwargs):
    if created:
        my_room = LivingRoom()
        my_room.user = instance

Update

But, as bruno has already said it, Django's models.Model subclass's initializer is best left alone, or should accept *args and **kwargs matching the model's meta fields.

So, following better principles, you should probably have something like

class LivingRoom(models.Model):
    '''Living Room object'''
    user = models.OneToOneField(User)

    def __init__(self, *args, temp=65, **kwargs):
        self.temp = temp
        return super().__init__(*args, **kwargs)

Note - If you weren't using temp as a keyword argument, e.g. LivingRoom(65), then you'll have to start doing that. LivingRoom(user=instance, temp=66) or if you want the default (65), simply LivingRoom(user=instance) would do.

I got the same error.

On my view I was overriding get_form_kwargs() like this:

class UserAccountView(FormView):
    form_class = UserAccountForm
    success_url = '/'
    template_name = 'user_account/user-account.html'

def get_form_kwargs(self):
    kwargs = super(UserAccountView, self).get_form_kwargs()
    kwargs.update({'user': self.request.user})
    return kwargs

But on my form I failed to override the init() method. Once I did it. Problem solved

class UserAccountForm(forms.Form):
    first_name = forms.CharField(label='Your first name', max_length=30)
    last_name = forms.CharField(label='Your last name', max_length=30)
    email = forms.EmailField(max_length=75)

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user')
        super(UserAccountForm, self).__init__(*args, **kwargs)