diff --git a/addons/http_routing/models/ir_http.py b/addons/http_routing/models/ir_http.py
index 3388aabeb80..068ee48ff4f 100644
--- a/addons/http_routing/models/ir_http.py
+++ b/addons/http_routing/models/ir_http.py
@@ -43,7 +43,7 @@ def _guess_mimetype(ext=False, default='text/html'):
     return ext is not False and exts.get(ext, default) or exts
 
 
-def slugify_one(s, max_length=None):
+def slugify_one(s, max_length=0):
     """ Transform a string to a slug that can be used in a url path.
         This method will first try to do the job with python-slugify if present.
         Otherwise it will process string by stripping leading and ending spaces,
@@ -61,13 +61,12 @@ def slugify_one(s, max_length=None):
         except TypeError:
             pass
     uni = unicodedata.normalize('NFKD', s).encode('ascii', 'ignore').decode('ascii')
-    slug_str = re.sub('[\W_]', ' ', uni).strip().lower()
-    slug_str = re.sub('[-\s]+', '-', slug_str)
-
-    return slug_str[:max_length]
+    slug_str = re.sub(r'[\W_]', ' ', uni).strip().lower()
+    slug_str = re.sub(r'[-\s]+', '-', slug_str)
+    return slug_str[:max_length] if max_length > 0 else slug_str
 
 
-def slugify(s, max_length=None, path=False):
+def slugify(s, max_length=0, path=False):
     if not path:
         return slugify_one(s, max_length=max_length)
     else: