properties.py

# -*- coding: utf-8 -*-

class Profile(models.Model):
  foo = models.CharField()
  user = models.ForeignKey(User)
  
  @property
  def first_name(self):
    return self.user.first_name

  @first_name.setter
  def first_name(self, value):    
    self.user.first_name = value

  def save(self, *args, **kwargs):
    self.user.save()
    super(Profile, self).save(*args, **kwargs)