Lina, the case you should use is ACCUSATIVE. (#4), which we are using for explanation of DIRECTION. ( Francuska, Framcuske, Francuskoj, FRANCUSKU, Francuska, Francuskom, Francuskoj ). You will got it on the questions: koga ? šta ? KUDA ?. And it is in use with the prepositions: uz, niz, nad, pod, kroz, za, niz, na, u, o, po, medju, pred ...
If you need some more information, let me know.
Kamenko