diff --git a/noisettes/header/header.html b/noisettes/header/header.html
index d790408b2a3164298347559e5880a30bb025b49d..422f590d5d121c1bc7f6645af0142a5a48f3f34a 100644
--- a/noisettes/header/header.html
+++ b/noisettes/header/header.html
@@ -1,6 +1,6 @@
 <!DOCTYPE HTML>
-<html xmlns="http://www.w3.org/1999/xhtml" lang="#LANG" xml:lang="#LANG" dir="#LANG_DIR">
-<head><meta charset="#CHARSET">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="#LANG" xml:lang="#LANG" dir="#LANG_DIR" prefix="og: http://ogp.me/ns#">
+<head><meta charset="#CHARSET" />
 <title>[(#ENV{title}) - ][(#NOM_SITE_SPIP|textebrut)]</title>
 [(#REM) FaceBook Open Graph : https://developers.facebook.com/docs/opengraphprotocol/ & https://developers.facebook.com/tools/lint pour vï¿½rifier ]
 <meta property="og:title" content="[(#ENV{title}|sinon{[(#NOM_SITE_SPIP|textebrut|attribut_html)]})]" />