diff --git a/src/lib_bls12_381_polynomial/test/test_main.ml b/src/lib_bls12_381_polynomial/test/test_main.ml
index 879046d9fef3daf93861014af2871bbd17b7cd47..f31834b131a9e245c83a1ee80b6137b033025328 100644
--- a/src/lib_bls12_381_polynomial/test/test_main.ml
+++ b/src/lib_bls12_381_polynomial/test/test_main.ml
@@ -50,7 +50,7 @@ let () =
                 RANDOM_SEED' in your terminal?"
                v))
   in
-  Printf.printf "Random seed: %d\n" seed ;
+  Format.printf "lib_bls12_381_polynomial random seed: %d%!" seed ;
   Random.init seed ;
   Alcotest.run
     ~__FILE__