diff --git a/alto_tools.py b/alto_tools.py
index 9d40253..5e2ff19 100755
--- a/alto_tools.py
+++ b/alto_tools.py
@@ -25,7 +25,8 @@ def alto_parse(alto):
     namespace = {'alto-1': 'http://schema.ccs-gmbh.com/ALTO',
                  'alto-2': 'http://www.loc.gov/standards/alto/ns-v2#',
                  'alto-3': 'http://www.loc.gov/standards/alto/ns-v3#',
-                 'alto-4': 'http://www.loc.gov/standards/alto/ns-v4#'}
+                 'alto-4': 'http://www.loc.gov/standards/alto/ns-v4#',
+                 'alto-bnf': 'http://bibnum.bnf.fr/ns/alto_prod'}
     # Extract namespace from document root
     if 'http://' in str(xml.getroot().tag.split('}')[0].strip('{')):
         xmlns = xml.getroot().tag.split('}')[0].strip('{')