Visa Z vs Transit G type

Hello,
I have French nationality.
I have the work Z type. As far as I know, with this Z type, once I enter the China, I have to stay there until I get the residence permit.
The problem is that I first want to go to Seoul for my holidays.
The cheapest way I found is, I first fly to Shanghai. I stay in Shanghai one night, and take a flight to Seoul the day after.
Can I request for a transit G type or, the utilization of work Z type is mandatory for 1 night?