我在德国使馆主页看的,中国护照的不用转机签证。
以下情况需申请visitor visa:
1. if you have to pick up your baggage and/or have to check-in again (please
verify with your airline).
2. if you are transiting through two or more airports in the Schengen
Countries (for example: Miami-Frankfurt-Paris-India)
3. if you hold an open ticket
4. if your stay in the international transit area exceeds 12 hours.
我也是从美国到法兰克福转机回北京,且美国visa已过期。