diff --git a/pn-dispatcher/src/main/java/info/papyri/dispatch/browse/facet/Facet.java b/pn-dispatcher/src/main/java/info/papyri/dispatch/browse/facet/Facet.java
index 9f5f9f42..35c8e661 100644
--- a/pn-dispatcher/src/main/java/info/papyri/dispatch/browse/facet/Facet.java
+++ b/pn-dispatcher/src/main/java/info/papyri/dispatch/browse/facet/Facet.java
@@ -329,7 +329,8 @@ public Boolean addConstraints(Map<String, String[]> params) {
 
           String param = java.net.URLDecoder.decode(values[i], "UTF-8");
 
-          if (param != null && !param.equals("default") && !param.equals("")) {
+          if (param != null && !param.equals("default") && !param.equals("")
+              && !param.contains("<") && !param.contains(">") && !param.contains(";")) {
             addConstraint(param);
             hasConstraint = true;
           }