Index: django/contrib/admin/templatetags/admin_list.py
===================================================================
--- django/contrib/admin/templatetags/admin_list.py     (revision 3905)
+++ django/contrib/admin/templatetags/admin_list.py     (working copy)
@@ -152,7 +152,7 @@
             # FloatFields are special: Zero-pad the decimals.
             elif isinstance(f, models.FloatField):
                 if field_val is not None:
-                    result_repr = ('%%.%sf' % f.decimal_places) % field_val
+                    result_repr = ('%%.%sf' % f.decimal_places) % float(field_val)
                 else:
                     result_repr = EMPTY_CHANGELIST_VALUE
             # Fields with choices are special: Use the representation