diff --git a/runtime/starpu/control/runtime_tags.c b/runtime/starpu/control/runtime_tags.c
index ad075ca6a2af61c050970c33ccf64ca72d1b9574..31cc94090a074d7ff6ae05b5d3f187767996ff01 100644
--- a/runtime/starpu/control/runtime_tags.c
+++ b/runtime/starpu/control/runtime_tags.c
@@ -129,8 +129,8 @@ chameleon_starpu_tag_book( int64_t nbtags )
     }
 
 #if defined(CHAMELEON_DEBUG_STARPU)
-    fprintf( stderr, "chameleon_starpu_tag: Book %ld - %ld\n",
-             min, min + nbtags );
+    fprintf( stderr, "[%02d] chameleon_starpu_tag: Book %ld - %ld\n",
+             CHAMELEON_Comm_rank(), min, min + nbtags );
 #endif
 
     assert( cst_first != NULL );