diff -r 2cfeb340dacf -r cdf63a1c7dc9 src/pyams_content/shared/site/interfaces.py
--- a/src/pyams_content/shared/site/interfaces.py	Wed Nov 06 16:54:59 2019 +0100
+++ b/src/pyams_content/shared/site/interfaces.py	Tue Nov 19 16:39:10 2019 +0100
@@ -9,6 +9,8 @@
 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
 # FOR A PARTICULAR PURPOSE.
 #
+from pyams_content.shared.common.interfaces.types import DATA_TYPES_VOCABULARY
+
 
 __docformat__ = 'restructuredtext'
 
@@ -149,6 +151,11 @@
 class IWfSiteTopic(IWfTopic, IInternalReferencesList):
     """Site topic interface"""
 
+    data_type = Choice(title=_("Data type"),
+                       description=_("Type of content data"),
+                       required=False,
+                       vocabulary=DATA_TYPES_VOCABULARY)
+
 
 class IWfSiteTopicFactory(IWfTopicFactory):
     """Topic factory interface"""