diff --git a/radicale/storage.py b/radicale/storage.py
index e1e1609..b3ef778 100644
--- a/radicale/storage.py
+++ b/radicale/storage.py
@@ -1420,7 +1420,8 @@ class Collection(BaseCollection):
         return (self.get(href, verify_href=False) for href in self.list())
 
     def get_all_filtered(self, filters):
-        tag, start, end, simple = xmlutils.simplify_prefilters(filters)
+        tag, start, end, simple = xmlutils.simplify_prefilters(
+            filters, collection_tag=self.get_meta("tag"))
         if not tag:
             # no filter
             yield from ((item, simple) for item in self.get_all())
diff --git a/radicale/xmlutils.py b/radicale/xmlutils.py
index 5bd2ae0..29bf72c 100644
--- a/radicale/xmlutils.py
+++ b/radicale/xmlutils.py
@@ -578,7 +578,7 @@ def _param_filter_match(vobject_item, filter_, parent_name, ns):
         return condition
 
 
-def simplify_prefilters(filters):
+def simplify_prefilters(filters, collection_tag="VCALENDAR"):
     """Creates a simplified condition from ``filters``.
 
     Returns a tuple (``tag``, ``start``, ``end``, ``simple``) where ``tag`` is
@@ -590,6 +590,9 @@ def simplify_prefilters(filters):
     flat_filters = tuple(chain.from_iterable(filters))
     simple = len(flat_filters) <= 1
     for col_filter in flat_filters:
+        if collection_tag != "VCALENDAR":
+            simple = False
+            break
         if (col_filter.tag != _tag("C", "comp-filter") or
                 col_filter.get("name").upper() != "VCALENDAR"):
             simple = False