diff --git a/src/libexpr/flake/config.cc b/src/libexpr/flake/config.cc
index 3e9d264b4..6df95f1f0 100644
--- a/src/libexpr/flake/config.cc
+++ b/src/libexpr/flake/config.cc
@@ -68,7 +68,7 @@ void ConfigFile::apply()
                 }
             }
             if (!trusted) {
-                warn("ignoring untrusted flake configuration setting '%s'", name);
+                warn("ignoring untrusted flake configuration setting '%s'.\nPass '%s' to trust it", name, "--accept-flake-config");
                 continue;
             }
         }