I would like to get tips on how I could evaluate my manager or my boss without being unjust.
So, is this question on topic here?
I would say it's not, unless there's some specific aspect to it that's related to software development. Otherwise it's just a question about interpersonal relationships in an office settings.
CareerOverflow.com may be a better place for it.
As Anna says, by itself "How to evaluate your manager" is not a problem with any specific relation to programming (yes, programmers do it, but so does everyone).
It's "on-topicness" depends on how you qualify it.
You say your problem is how to evaluate your manager "without being unjust" — this doesn't sound like a problem that is unique to developers. However, I can imagine a few variations that would be on topic:
Think about what ways your question can be answered uniquely by programmers, and make sure to ask the question in a way that solicits those answers.