How to react to strongly erroneous and irrelevant citation of my article? In an paper, an author cites my article in which he states that I said "something" and that it is wrong. Not only have I never said "something", but the article he cites is about a completely different topic (there is no ambiguity about that).

Obviously the reviewers have not done their job appropriately, but that it too late. Worth mentioning I suspect this is due to my non-responding to his solicitations, but that is not the point here (see edit).

How should I react (ethically) to that?



Clarifications

This question was marked as a duplicate but I will add a few clarifications out of respect for the commenters/answerers: I did not expand too much on the solicitations because I did not find it very relevant. What happened is that I was approach by a researcher who wanted to extend his research topic to mine (or more generally to that of the company I'm working for). He invited me to contribute to some funding project, which I did, then asked me some technical questions, to which I answered, up to a point where I got annoyed by him not reading the references I suggested. He basically wanted me to spoonfeed him everything. He then cited my article in a negative manner, including a completely false statement (that I said in my article that a solver had property X when the cited article does not even mention anything related to a solver -- and it's not just citing the wrong article: I never wrote anything related to this wrong statement).
Begin by trying to speak to the author and see what he says.  Then:

Speak to the editor of the journal, unless the author is willing to submit a correction instead.  If the problem is big enough that it:

a) Misrepresents your work to the degree that someone would think, from this article's citation alone, that you did or did not do something critical, or

b) Invalidates the results of the paper in which the citation is published, or

c) Undermines those results by providing a false citation to make it look like a claim is better supported than it is

then it is important that the editor be involved and the article be corrected.

If it's a small problem, then speaking to the editor may not do much.  As an example, a paper of mine was cited incorrectly once.  It was actually a small and irrelevant mistake, and the authors probably meant to cite something else.  It was along the lines of: "Other techniques to solve this problem include Y, which was explored in [1][2][3], but we are approaching it differently" and that was it.  In this case, embarrassing the author was not something I felt like doing so I let it go.