diff --git a/Packages/Sweep_line_2/include/CGAL/Sweep_line_tight_2.h b/Packages/Sweep_line_2/include/CGAL/Sweep_line_tight_2.h
index 4f7f134d221..10bd23e6aba 100644
--- a/Packages/Sweep_line_2/include/CGAL/Sweep_line_tight_2.h
+++ b/Packages/Sweep_line_2/include/CGAL/Sweep_line_tight_2.h
@@ -31,7 +31,7 @@
 
 #include <map>
 #include <set>
-
+#include <assert.h>
 
 #ifndef VERBOSE
 
@@ -59,10 +59,10 @@
 #define STORE_RESULT(a) {a}
 #endif
 
+#include <list>
 
 CGAL_BEGIN_NAMESPACE
 
-
 /*!
   Sweep_line_tight_2 is a class that implements the sweep line algorithm
   based on the algorithm of Bentley and Ottmann.