formatters.py

# -*- coding: utf-8 -*-
from django.template.defaultfilters import floatformat
from django.contrib.humanize.templatetags.humanize import intcomma
from django.utils.encoding import force_unicode

from django.template import Library
 
register = Library()
 
@register.filter(name='float_to_real') 
def float_to_real(value, precision):
    '''
    Receives a Float instance and returns a string formatted as brazilian Real currency:
    12.345,67. Without the "R$".
    '''
    value_arg = floatformat(value, precision)
    value_arg, float_arg = force_unicode(value_arg).split(',')
    value_arg = intcomma(value_arg)
    value_arg = value_arg + ',' + float_arg
    return value_arg

formfields.py

from django import forms

from widgets import RealCurrencyInput

class RealCurrencyField(forms.DecimalField):
    widget = RealCurrencyInput
    
    def clean(self, value):
        if value:
            value = value.replace('.', '').replace(',','.')
        return super(RealCurrencyField, self).clean(value)
    
    def widget_attrs(self, widget):
        return {'class':'real_currency'}

widgets.py

from decimal import Decimal

from django import forms
from django.utils.safestring import mark_safe

from formatters import decimal_to_real

class RealCurrencyInput(forms.TextInput):
    
    def render(self, name, value, attrs=None):
        value = value or ''
        if isinstance(value, Decimal):
            value = decimal_to_real(str(value), 2)
        attrs = attrs or {}
        attrs['class'] = 'real'
        attrs['alt'] = 'decimal'
        html = super(RealCurrencyInput, self).render(name, value, attrs)
        return mark_safe(u"R$ " + html)