diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/dto/ParameterValue.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/dto/ParameterValue.java
index 38b0a31e3fac4f21ea1c4e77b072aef2957f3035..26ed284edff45496911a3067922832bf175a2555 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/dto/ParameterValue.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/dto/ParameterValue.java
@@ -100,7 +100,7 @@ public class ParameterValue implements Comparable<ParameterValue>, IsSerializabl
 
     public int compareTo(ParameterValue o)
     {
-        return this.value.compareTo(o.value);
+        return toString().compareTo(o.toString());
     }
 
 }