144 hr or 72hr Visa Free valid

Yes, your itinerary, under the condition that you have mentioned your all stops, is definitely eligible for 144 hour visa free transit in Shanghai area.

Thanks zupan for your kind reply. Seems cet simple. however, tried to have confirmation calling british Airways. I have spoken to someone from commercial relationship. Thé answer was you need a visa which seems to Be BA policy that's all. Then I explain check trough TOMATIC or IATA where it's precisely explain roulés about 144H transit visa but at the end thé answer has been " not aware " try to Be un touche with chinese consulats....So , no clear answer from BA customer reliationship door.
I am afraid arriving at CDG Paris BA registration desk in front of people un futur which don't accept to deliver my boarding card.
Up to nos, I didn't succeed to join thé staff involved un supplying boarding cards.

Tori, the staff of every airline customer support is plainly speaking - stupid. They are a synonym for the noun stupidity. They can support or help you just in usual cases, but they will never, remember - never answer precisely and accurately to the question of your kind. Also, you will get similar response from the Chinese consulates because visa free transit within China is definitely not their jurisdiction, but this is the field of Chinese immigration.

By the way, now I'm becoming a bit suspicious about your itinerary because it was originally:

US - London - Shanghai - US

And now you are introducing Paris???

It is OK if your itinerary is:

US - Paris - London - Shanghai - US

Anyway, now I'm afraid that you might have some additional surprises within your itinerary. You have to know that you are allowed to have only one stop within mainland China to be eligible for 144 hour visa free transit!

The only people that really know about the details regarding the visa free transit through China is an airport staff that is used to consult Timatic on daily basis. It is extremely hard to reach them on the phone and you really don't even try to do that because you just have to create an eligible itinerary and you will be definitely allowed to enjoy 144 hour visa free transit in your chosen Chinese destination.

To support Zupan's advice, it is our firm and repeated advice that calling airlines or consulates is always a waste of time. Even if they give you a verbal assurance on the phone, that is completely worthless once you are at the airport to check-in. Entry requirements and visa rules can change between now and then, and the only decision makers are the airline staff at the airport on the day of travel. They will be trained in consulting Timatic.

I am also confused about the itinerary here, by the way.