Start by naming any country that France borders. Then name any country that borders any of those countries. Then keep going until there are no more countries left to name.
No it was not a client state. France defeated Austria multiple times and to punish it, France annexed all of Austria's coastal access which created those weird borders.
Uh... ahm... where to start? I basically go through a lot of sources for map and compare them if there's a lack of information. Inkscape is my go-to map making software.