Dear Julielai,
actaully it is what i came across in my reading of another legal paper in English but written by a German. in that paper, it refers to a bank of Hamburge.
I've looked it up in my English Chinese Law Dictionary which gives the meaning as "???". and i made a research of ??? in google and got this
http://www.get.com.tw/goldensun/answer/K01(ok).doc
seems that a public law instition is a government body or social orginization.
that paper above mentioned concerns with the transformation of that German bank into a limited company. Maybe prior to that transformation it is a public law institution
BTW, i noted you run a website or may be just a member thereof, anyway i'll have a look if i get the time.
Have a good day!
Vincent
Tianjin, China