diff --git a/Classification/include/CGAL/Classification/ETHZ_random_forest_classifier.h b/Classification/include/CGAL/Classification/ETHZ_random_forest_classifier.h
index 12db1189a0b..c076b34896b 100644
--- a/Classification/include/CGAL/Classification/ETHZ_random_forest_classifier.h
+++ b/Classification/include/CGAL/Classification/ETHZ_random_forest_classifier.h
@@ -25,6 +25,7 @@
 
 #include <CGAL/Classification/Feature_set.h>
 #include <CGAL/Classification/Label_set.h>
+#include <CGAL/Classification/internal/verbosity.h>
 
 #ifdef CGAL_CLASSIFICATION_VERBOSE
 #define VERBOSE_TREE_PROGRESS 1
@@ -43,6 +44,8 @@
 #include <CGAL/Classification/internal/auxiliary/random-forest/node-gini.hpp>
 #include <CGAL/Classification/internal/auxiliary/random-forest/forest.hpp>
 
+#include <CGAL/tags.h>
+
 #include <boost/archive/text_iarchive.hpp>
 #include <boost/archive/text_oarchive.hpp>
 #include <boost/iostreams/filtering_stream.hpp>
diff --git a/Classification/include/CGAL/Classification/internal/auxiliary/random-forest/forest.hpp b/Classification/include/CGAL/Classification/internal/auxiliary/random-forest/forest.hpp
index 6dd83485e76..02d326f8c76 100644
--- a/Classification/include/CGAL/Classification/internal/auxiliary/random-forest/forest.hpp
+++ b/Classification/include/CGAL/Classification/internal/auxiliary/random-forest/forest.hpp
@@ -45,6 +45,8 @@
 #include <cstdio>
 #endif
 
+#include <CGAL/tags.h>
+
 #ifdef CGAL_LINKED_WITH_TBB
 #include <tbb/parallel_for.h>
 #include <tbb/blocked_range.h>