I have come across this answer which may answer the question, but why on Earth would the answerer provide their solution in French? Meanwhile, the question is in English and I see no request for a French answer, there is an accepted answer with 7 upvotes and a duplicate one. I mean, if all of us start providing answers in different languages, SO would become a mess. Shouldn't some language guidelines be followed?
I went to investigate other answers of the user who answered and it seems that his other answers are a bit irrelevant to the questions. I am not a C# expert so I shouldn't really judge, but those answers are low-quality (can't bear the truth).
I have flagged the answer for moderator's attention, giving a custom reason, but I'm not sure that's the right thing to do.
It's a bit of a strange case, so I would appreciate any advice on what to do in such cases?