Wait, why was Germany right to invade France? As for territorial disputes, most countries have moved on from arguing over small pieces of land, the consequences would far out weigh the positive results (though Argentina didn't learn its lesson, but there is oil there, so...). If Spain attacked Gibraltar, even if they took the land, they would get raped the British, and they would lose a lot of trade. Alsace and Lorraine had been part of France for quite a while, and the land was valuable. They formed a large part of French thinking, only the extreme left parties wouldn't have cared about it.
Also Jack Klein: France started the Franco-Prussian War, but they were goaded into doing it by Bismark, who tampered with communications between the two countries.