diff --git a/app/assets/stylesheets/_maintenance.scss b/app/assets/stylesheets/_maintenance.scss
new file mode 100644
index 000000000..dd59c31d6
--- /dev/null
+++ b/app/assets/stylesheets/_maintenance.scss
@@ -0,0 +1,15 @@
+.maintenance {
+  width: 100%;
+  position: fixed;
+  top: 0;
+  z-index: 100;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+
+  span {
+    margin: auto;
+    background: #FFD8A6;
+    padding: 0 4px;
+  }
+}
diff --git a/app/assets/stylesheets/application.scss b/app/assets/stylesheets/application.scss
index f2c861d76..e163c9274 100644
--- a/app/assets/stylesheets/application.scss
+++ b/app/assets/stylesheets/application.scss
@@ -12,6 +12,7 @@
 // defined in the other CSS/SCSS files in this directory. It is generally better to create a new
 // file per style scope.
 //
+// = require _maintenance
 // = require _card
 // = require _helpers
 // = require _turbolinks
diff --git a/app/assets/stylesheets/new_design/_maintenance.scss b/app/assets/stylesheets/new_design/_maintenance.scss
new file mode 100644
index 000000000..153a5f685
--- /dev/null
+++ b/app/assets/stylesheets/new_design/_maintenance.scss
@@ -0,0 +1,8 @@
+@import "colors";
+
+.maintenance {
+  padding: 20px;
+  text-align: center;
+  width: 100%;
+  background: $orange-bg;
+}
diff --git a/app/views/layouts/_pre_maintenance.html.haml b/app/views/layouts/_pre_maintenance.html.haml
new file mode 100644
index 000000000..636556d16
--- /dev/null
+++ b/app/views/layouts/_pre_maintenance.html.haml
@@ -0,0 +1,4 @@
+- if Flipflop.pre_maintenance_mode?
+  .maintenance
+    %span
+      Une opération de maintenance est prévue sur demarches-simplifiees.fr à 23 h 00. La plateforme sera inaccessible pendant une vingtaine de minutes.
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 9c6640ace..79878e57e 100644
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -17,6 +17,7 @@
     = csrf_meta_tags
   %body
     = render partial: 'layouts/support_navigator_banner'
+    = render partial: 'layouts/pre_maintenance'
     - if Rails.env == 'staging'
       #beta
         Env Test
diff --git a/app/views/layouts/new_application.html.haml b/app/views/layouts/new_application.html.haml
index c214f26a0..daa786536 100644
--- a/app/views/layouts/new_application.html.haml
+++ b/app/views/layouts/new_application.html.haml
@@ -21,6 +21,7 @@
     .page-wrapper
       = render partial: "layouts/support_navigator_banner"
       = render partial: "layouts/ie_lt_10"
+      = render partial: 'layouts/pre_maintenance'
       - if Rails.env == "staging"
         #beta
           Env Test
diff --git a/config/features.rb b/config/features.rb
index 14e779b0c..2ef08cc14 100644
--- a/config/features.rb
+++ b/config/features.rb
@@ -22,5 +22,6 @@ Flipflop.configure do
       default: Rails.env.production?
   end
 
+  feature :pre_maintenance_mode
   feature :maintenance_mode
 end
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
index 68eebcf50..e45172e74 100644
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -150,7 +150,7 @@ Devise.setup do |config|
   # ==> Configuration for :timeoutable
   # The time you want to timeout the user session without activity. After this
   # time the user will be asked for credentials again. Default is 30 minutes.
-  config.timeout_in = 24.hours
+  config.timeout_in = 1.hour
 
   # If true, expires auth token on session timeout.
   # config.expire_auth_token_on_timeout = false
diff --git a/db/migrate/20180502092852_remove_parent_procedure_foreign_key.rb b/db/migrate/20180502092852_remove_parent_procedure_foreign_key.rb
new file mode 100644
index 000000000..5b466f851
--- /dev/null
+++ b/db/migrate/20180502092852_remove_parent_procedure_foreign_key.rb
@@ -0,0 +1,5 @@
+class RemoveParentProcedureForeignKey < ActiveRecord::Migration[5.2]
+  def change
+    remove_foreign_key :procedures, column: "parent_procedure_id"
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index eec9b4f96..c1b888d2c 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_04_24_130548) do
+ActiveRecord::Schema.define(version: 2018_05_02_092852) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -574,7 +574,6 @@ ActiveRecord::Schema.define(version: 2018_04_24_130548) do
   add_foreign_key "procedure_paths", "administrateurs"
   add_foreign_key "procedure_paths", "procedures"
   add_foreign_key "procedure_presentations", "assign_tos"
-  add_foreign_key "procedures", "procedures", column: "parent_procedure_id"
   add_foreign_key "received_mails", "procedures"
   add_foreign_key "refused_mails", "procedures"
   add_foreign_key "without_continuation_mails", "procedures"