It's a slightly difficult question to answer easily, but I'll give it a burl. :) I'd say there's a slight sense of distance, as "to someone" means that someone receives something into their hands, whereas "for someone" just means the person is the reason for (or benefits from) the action. Compare: "I carried a basket to my sister" and "I carried a basket for my sister". So, because Parisians live in Paris and Paris is the topic at hand, then "to Parisians" makes most sense here. (If anyone else is willing to tackle this, I'm also keen to hear a second opinion.)

其实我觉得在这里，没有多大的区别，都可以。就比如，在中文里，又可以说“对巴黎人来说”，又可以说“在巴黎人的眼里”等。关键是to和for这些词语的用法很广泛，每个语境里的含义可能有所不一样。反正，在你的那个例句里，我觉得没什么区别。

Interesting question. I think one way to decide whether to use "to" or "for" is to re-organize the sentence. A: Is she nice? B: To me, she's always been nice. (She's always been nice to me.) Your example sentence would be still be correct if using "for" both times or "to" both times. "Paris is a place to live for Parisians, but Paris is a place to dream for Americans." Your example is better because it emphasizes the contrast between French and Americans. A: How was the test? B: I thought it was easy. A: How about your friend Alex? B: For him, it was not so easy. You could say, "It was not so easy for him." But you want to emphasize who the sentence is about. Some of this may simply be how things sound to a native speaker. After a while, you just get a feel for it.

It would be proper English to say. "To Parisians, Paris is a place to live, but to Americans, it's a place to dream" as well, "For Parisians, Paris is a place to live, but for Americans, it's a place to dream" Either is correct. However, the author has a bias or a subliminal intention. "To me" is bad, "For me" is good.

"for me" is good. If someone did something for me. I'm happy. It's an act of kindness. However, If someone did something "to me" it could mean literally, i.e., a message. But, more likely, it means something bad. If someone did something to me I probably didn't like it. I'm angry about it.