French passport flying from Singapore to Shanghai

Hello,
I hold a French passport and am currently in Singapore with tourist visa. Can I fly direct to Shanghai, spend less than the 144h/6 days there and come back to Singapore with direct flight?
if not, then other option would be to fly from Singapore to Hong-Kong (no visa needed), then to Shanghai for less than 144h, and return direct to Singapore I guess.

Thanks for the help,
Best,
Marie