diff --git a/ChangeLog b/ChangeLog
index 5ad49dc9c..12fe15694 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2008-03-10  Bastien Guerry  <bzg@altern.org>
 
+	* org-publish.el (org-publish-file): Send an error when file is
+	not part of any project.
+
 	* org.el (org-select-remember-template): Cleaned the code.
 
 	* org-publish.el (org-publish-before-export-hook)
diff --git a/org-publish.el b/org-publish.el
index 0385a3774..09110061d 100644
--- a/org-publish.el
+++ b/org-publish.el
@@ -516,7 +516,10 @@ FILENAME is the filename of the file to be published."
 (defun org-publish-file (filename &optional project)
   "Publish file FILENAME from PROJECT."
   (when (org-publish-needed-p filename)
-    (let* ((project (or project (org-publish-get-project-from-filename filename)))
+    (let* ((project (or project 
+			(or (org-publish-get-project-from-filename filename)
+			    (error "File %s is not part of any known project" 
+				   filename))))
 	   (project-plist (cdr project))
 	   (publishing-function (or (plist-get project-plist :publishing-function)
 				    'org-publish-org-to-html))