diff --git a/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py b/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
index 83f03359983d14df74fc197f234dcf26b17d5be7..361a4d227a3ad9c5c93cf969b21fdef5d514e401 100644
--- a/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
+++ b/library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py
@@ -810,12 +810,14 @@ class CLUnfolder(object):
         if self.__locked:
             raise MCLException("Trying to compile property while unfolder is locked")
 
-        # syntax analyser and type checker
-        # property_text, symb_t, reporter
-        tree_prop = compile_cond(property_text,
-                                 self.__dyn_sys.symb_tab,
-                                 self.__dyn_sys.report)
-        # avoid name collisions of aux var
+        # Syntax analyser and type checker
+        # Compile a condition expression to a tree representation
+        tree_prop = compile_cond( ## TODO: AUDIT
+            property_text,
+            self.dynamic_system.symb_tab,
+            self.dynamic_system.report
+        )
+        # Avoid name collisions of aux var
         prop_visitor = CLPropertyVisitor(self.__lit_cpt)
         tree_prop.accept(prop_visitor)
         self.__lit_cpt = prop_visitor.cpt # avoid name collisions of aux var
@@ -836,10 +838,14 @@ class CLUnfolder(object):
             raise MCLException("Trying to compile property while unfolder is locked")
 
         # Syntax analyser and type checker
+        # Compile an event expression to a tree representation
+        # tree_prop is the event expression,
+        # ste the state events (s#> ..) used and
+        # fcl is the free clocks used in the event expression.
         tree_prop, ste, fcl = compile_event(
             property_text,
             self.dynamic_system.symb_tab,
-            True,
+            True, # Collect free clocks (events)
             self.dynamic_system.report
         )
         # Avoid name collisions of aux var