diff --git a/poincare/include/poincare/tree_pool.h b/poincare/include/poincare/tree_pool.h
index a124964e3..36bce5366 100644
--- a/poincare/include/poincare/tree_pool.h
+++ b/poincare/include/poincare/tree_pool.h
@@ -27,7 +27,8 @@ public:
 
   // Node
   TreeNode * node(int identifier) const {
-    assert(identifier >= 0 && identifier <= MaxNumberOfNodes);
+    assert(identifier >= 0 && identifier < MaxNumberOfNodes);
+    assert(m_nodeForIdentifier[identifier] != nullptr);
     return m_nodeForIdentifier[identifier];
   }