diff -r a2342f26c9de -r b0b56e0f8c7f server/bo_client/app/instance-initializers/i18n.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/server/bo_client/app/instance-initializers/i18n.js	Fri Jan 15 15:35:00 2016 +0100
@@ -0,0 +1,11 @@
+export default {
+  name: 'i18n',
+  initialize: function( instance ) {
+    instance.lookup('service:i18n').set('locale', calculateLocale());
+  }
+};
+
+function calculateLocale() {
+  // whatever you do to pick a locale for the user:
+  return navigator.language || navigator.userLanguage || 'fr-FR';
+}