✔ 最佳答案
French is very useful in France (of course, because still many French don't speak English well), French speaking part of Switzerland (ie. Geneva, Lausanne, etc), Tunisia and Greece.
German - also a good choice and would be "easier" than French because Grammar has more rules than French (French have more exceptions than rules)
Spanish - VERY USEFUL because not only in Spain but Italians, Portuguese, most countries in Latin America understand it
I would not encourage you learning the minority language.