1 day visit/visa to Shenzhen (Hong Kong)

Hi,

I have a french passport and a Hong Kong ID, but no visa to China.

I heard that, as a Hong Kong resident, I can go to Shenzhen for the day without applying for a chinese visa.
It seems that there is a one day/temparary visa, but I do not know how it works and how and where to apply. Is it at the Lowu border ?

It also seems that for french people, it seems to be more complicated because of the bad diplomatic relationship between France and China.

Thank you for the information you could have.

Véronique