<!DOCTYPE html>
-<html{% if lang is defined and lang %} lang="{{ lang }}"{% endif %}>
+<html{% if app.request.locale is defined and app.request.locale %} lang="{{ app.request.locale }}"{% endif %}>
<head>
{% block metas %}<meta charset="UTF-8">{% endblock %}
<title>{% block title %}Welcome!{% endblock %}</title>