diff --git a/app/models/locomotive/extensions/site/locales.rb b/app/models/locomotive/extensions/site/locales.rb
index df1a5cf6..206132a8 100644
--- a/app/models/locomotive/extensions/site/locales.rb
+++ b/app/models/locomotive/extensions/site/locales.rb
@@ -10,8 +10,12 @@ module Locomotive
           ## fields ##
           field :locales, :type => 'RawArray', :default => []
 
+          ## validations ##
+          validate :can_not_remove_default_locale
+
           ## callbacks ##
-          after_validation :add_default_locale
+          after_validation  :add_default_locale
+          before_update     :verify_localized_default_pages_integrity
 
         end
 
@@ -48,6 +52,10 @@ module Locomotive
           self.locales.first || Locomotive.config.site_locales.first
         end
 
+        def default_locale_was
+          self.locales_was.first || Locomotive.config.site_locales.first
+        end
+
         def locale_fallbacks(locale)
           [locale.to_s] + (locales - [locale.to_s])
         end
@@ -58,6 +66,29 @@ module Locomotive
           self.locales = [Locomotive.config.site_locales.first] if self.locales.blank?
         end
 
+        def can_not_remove_default_locale
+          if self.persisted? && !self.locales.include?(self.default_locale_was)
+            self.errors.add :locales, I18n.t(:default_locale_removed, :scope => [:errors, :messages, :site])
+          end
+        end
+
+        def verify_localized_default_pages_integrity
+          if self.persisted? && self.locales_changed?
+            self.pages.where(:"slug.#{self.default_locale_was}".in => %w(index 404), :depth => 0).each do |page|
+              modifications = { 'title' => {}, 'slug' => {} }
+
+              self.locales.each do |locale|
+                slug = page.attributes['slug'][self.default_locale_was]
+
+                modifications['slug'][locale]  = slug
+                modifications['title'][locale] = page.attributes['title'][locale] || ::I18n.t("attributes.defaults.pages.#{slug}.title", :locale => locale)
+              end
+
+              page.collection.update({ :_id => page._id }, { '$set' => modifications })
+            end
+          end
+        end
+
       end
 
     end
diff --git a/config/locales/default.en.yml b/config/locales/default.en.yml
index 016cadf0..18ecdaa1 100644
--- a/config/locales/default.en.yml
+++ b/config/locales/default.en.yml
@@ -12,6 +12,8 @@ en:
         extname_changed: "New file does not have the original extension"
         array_too_short: "is too small (minimum element number is %{count})"
         invalid_theme_file: "can't be blank or isn't a zip file"
+        site:
+          default_locale_removed: The previous default locale can not be removed right away.
         page:
           liquid_syntax: "Liquid Syntax error ('%{error}' on '%{fullpath}')"
           liquid_extend: "The page '%{fullpath}' extends a template which does not exist"
diff --git a/config/locales/default.fr.yml b/config/locales/default.fr.yml
index 45d043ae..d3a9b332 100644
--- a/config/locales/default.fr.yml
+++ b/config/locales/default.fr.yml
@@ -33,6 +33,8 @@ fr:
       extname_changed: "Nouveau fichier n'a pas l'extension original"
       array_too_short: "est trop petit (le nombre minimum d'éléments est %{count})"
       security: "présente un problème de sécurité"
+      site:
+        default_locale_removed: La langue par défaut ne peut pas être supprimée de cette façon.
       page:
         liquid_syntax: "Erreur de syntaxe dans les sections de page, veuillez vérifier la syntaxe ('%{error}'/'%{fullpath}')"
         liquid_extend: "La page '%{fullpath}' étend le contenu d'une page qui n'existe pas"
diff --git a/spec/models/locomotive/site_spec.rb b/spec/models/locomotive/site_spec.rb
index 3d8ce016..a3c9722c 100644
--- a/spec/models/locomotive/site_spec.rb
+++ b/spec/models/locomotive/site_spec.rb
@@ -1,3 +1,5 @@
+# coding: utf-8
+
 require 'spec_helper'
 
 describe Locomotive::Site do
@@ -114,6 +116,47 @@ describe Locomotive::Site do
       @site.pages.map(&:fullpath).sort.should == %w{404 index}
     end
 
+    it 'translates the index/404 pages if a new locale is added' do
+      @site.update_attributes :locales => %w(en fr)
+
+      @site.errors.should be_empty
+
+      ::Mongoid::Fields::I18n.with_locale('fr') do
+        @site.pages.root.first.tap do |page|
+          page.title.should == "Page d'accueil"
+          page.slug.should == 'index'
+        end
+
+        @site.pages.not_found.first.tap do |page|
+          page.title.should == 'Page non trouvée'
+          page.slug.should == '404'
+        end
+      end
+    end
+
+    it 'translates the index/404 pages if the default locale changes' do
+      @site.update_attributes :locales => %w(fr en)
+
+      @site.errors.should be_empty
+
+      ::Mongoid::Fields::I18n.with_locale('fr') do
+        @site.pages.root.first.tap do |page|
+          page.title.should == "Page d'accueil"
+          page.slug.should == 'index'
+        end
+
+        @site.pages.not_found.first.tap do |page|
+          page.title.should == 'Page non trouvée'
+          page.slug.should == '404'
+        end
+      end
+    end
+
+    it 'does not allow to remove the default locale' do
+      @site.update_attributes :locales => %w(fr)
+      @site.errors[:locales].should == ['The previous default locale can not be removed right away.']
+    end
+
   end
 
   describe 'deleting in cascade' do