A lot of ethnic groups in Eastern Europe were not allowed to choose what country they would become part of. Italy annexed a lot of land inhabited by Slovenes and Croats. The rest of the Slovenes, Croats and Bosnian were handed over to Serbia--Yugoslavia was essentially a Greater Serbia. Even though the Montenegrins are mostly Serbian Orthodox in religion, apparently many of them would have preferred to keep their separate kingdom.
Alsace-Lorraine was taken from France in 1871 at the end of the Franco-Prussian War. France got it back after WWI. It may have been largely German-speaking at the time but had been part of France since the reign of Louis XIV and the people considered themselves French.
Screw the French, if Britain and Germany were aligned against France, the world would have been much better off.
Wait a minute. Elsass-Lothringen had been part of the Holy Roman Empire (of the German nation) for centuries. The French stole it in the 17th century. The Germans only took it BACK in the 19th century. The French then got very butt-hurt that the Germans reclaimed their stolen land. Anybody who has been there notices immediately that the architecture and place names are German. Anybody who hears the locals speak immediately recognizes it as a German dialect. When the Germans reclaimed it in 1871, nobody there protested it being part of Germany again. They were just fine with it.
Yes there were plenty of subject nationalities in Eastern Europe. I'm just pointing out the Germans had very legitimate grievances after Versailles. The Entente Powers shat all over the principles they claimed to believe in (democracy, no subject nationalities, government derives its legitimacy from the consent of the governed) etc. Also, its undeniable that the German minorities WERE discriminated against in Czechoslovakia and Poland and to a lesser extent, Italy.