diff --git a/src/traces/tracer.cpp b/src/traces/tracer.cpp
index a40c7ada1ec87264d9660024b23cad8a5be95e59..ec52a3a75026f4351747468730031adb199bbf9c 100644
--- a/src/traces/tracer.cpp
+++ b/src/traces/tracer.cpp
@@ -25,6 +25,7 @@
 /* DG */
 #include <dynamic-graph/tracer.h>
 #include <dynamic-graph/debug.h>
+#include <dynamic-graph/value.h>
 #include <dynamic-graph/pool.h>
 #include <dynamic-graph/factory.h>
 #include <dynamic-graph/all-commands.h>
@@ -32,6 +33,7 @@
 
 using namespace std;
 using namespace dynamicgraph;
+using namespace dynamicgraph::command;
 
 DYNAMICGRAPH_FACTORY_ENTITY_PLUGIN(Tracer,"Tracer");