Thermador ovens lock the door during and immediately after a self-clean cycle because the cavity reaches temperatures well above normal cooking range, and the lock mechanism is tied to a temperature sensor rather than a simple timer. In most cases, the door releases on its own once the cavity has fully cooled — which can take longer than it feels like it should after a long clean cycle.
Don’t force the door open. If it’s still locked well after the oven has had time to cool completely, or if the lock releases and re-engages unpredictably, that points to a sensor or control-board problem behind the lock logic rather than the oven simply still being hot — and that’s worth a technician visit rather than repeated attempts to force it.