diff --git a/src/h3.c b/src/h3.c
index 42289c0a5..94b50ba90 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1095,7 +1095,7 @@ static ssize_t h3_decode_qcs(struct qcs *qcs, struct buffer *b, int fin)
 			/* Check that content-length is not exceeded on a new DATA frame. */
 			if (ftype == H3_FT_DATA) {
 				h3s->data_len += flen;
-				if (h3s->flags & H3_SF_HAVE_CLEN && h3_check_body_size(qcs, fin))
+				if (h3s->flags & H3_SF_HAVE_CLEN && h3_check_body_size(qcs, (fin && flen == b_data(b))))
 					break;
 			}
 
@@ -1130,12 +1130,12 @@ static ssize_t h3_decode_qcs(struct qcs *qcs, struct buffer *b, int fin)
 			break;
 		}
 
-		/* Check content-length equality with DATA frames length on the last frame. */
-		if (fin && h3s->flags & H3_SF_HAVE_CLEN && h3_check_body_size(qcs, fin))
-			break;
-
 		last_stream_frame = (fin && flen == b_data(b));
 
+		/* Check content-length equality with DATA frames length on the last frame. */
+		if (last_stream_frame && h3s->flags & H3_SF_HAVE_CLEN && h3_check_body_size(qcs, last_stream_frame))
+			break;
+
 		h3_inc_frame_type_cnt(h3c->prx_counters, ftype);
 		switch (ftype) {
 		case H3_FT_DATA: