2 stops in China + passport validity

Hi!
I will be travelling from France to Japan as following :
Paris - Beijing - Tokyo - Shanghai - Paris
On my way back I am planning to get a 72h free transit in Shanghai. Is that ok since I won’t go out from the airport in Beijing. My travel is planned in April and my passport is expiring in July. Is it ok since I would be in a free situation?
Thanks for your help!
Camille