Stuart wasn't clear enough. GEM is a grande ecole, but it has different masters programmes. One of those degrees, the MiM, is *the* grande Ecole *programme* -
https://en.grenoble-em.com/masters-management-grande-ecole-program Generally, the FT MiM ranking includes those grande Ecole programmes. See the double star note after the degree name at:
http://rankings.ft.com/businessschoolrankings/masters-in-management-2019 The Grande Ecole programme leads to a masters degree from the French state.
GEM only runs the Grande Ecole programme on the Grenoble campus. The Paris campus has a different offer, the MIB. The MIB, as I understand it, does not lead to a degree from the French state. It leads to a diploma, Manager d'affaires internationales.
There is no European market for MiM graduates. There are national labour markets. I suggest you choose between the Czech Republic, Ireland, France etc on the basis of whether you speak better Czech, English, French etc.