diff --git a/src/h3.c b/src/h3.c
index e802d299c..ea512a404 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1615,7 +1615,23 @@ static size_t h3_snd_buf(struct qcs *qcs, struct htx *htx, size_t count)
  */
 static int h3_close(struct qcs *qcs, enum qcc_app_ops_close_side side)
 {
-	/* TODO */
+	struct h3s *h3s = qcs->ctx;
+	struct h3c *h3c = h3s->h3c;;
+
+	/* RFC 9114 6.2.1. Control Streams
+	 *
+	 * The sender
+	 * MUST NOT close the control stream, and the receiver MUST NOT
+	 * request that the sender close the control stream.  If either
+	 * control stream is closed at any point, this MUST be treated
+	 * as a connection error of type H3_CLOSED_CRITICAL_STREAM.
+	 */
+	if (qcs == h3c->ctrl_strm) {
+		TRACE_ERROR("closure detected on control stream", H3_EV_H3S_END, qcs->qcc, qcs);
+		qcc_emit_cc_app(qcs->qcc, H3_CLOSED_CRITICAL_STREAM, 1);
+		return 1;
+	}
+
 	return 0;
 }
 
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 401ccc0c1..cae22df1f 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -1232,6 +1232,13 @@ int qcc_recv_stop_sending(struct qcc *qcc, uint64_t id, uint64_t err)
 
 	qcs_idle_open(qcs);
 
+	if (qcc->app_ops->close) {
+		if (qcc->app_ops->close(qcs, QCC_APP_OPS_CLOSE_SIDE_WR)) {
+			TRACE_ERROR("closure rejected by app layer", QMUX_EV_QCC_RECV|QMUX_EV_QCS_RECV, qcc->conn, qcs);
+			goto out;
+		}
+	}
+
 	/* RFC 9000 3.5. Solicited State Transitions
 	 *
 	 * An endpoint that receives a STOP_SENDING frame