Fauteuil literally means armchair - I don’t know why Tatoeba has so many non-literal translations like this. It’s extremely inconvenient for language learners.
Missing the context, I can’t guess what is wrong.
But this sentence is perfectly fine by itself.
If one needs to say that he should physically go back to his seat which happens to be an armchair, one would say this sentence.
Yes but we are trying to translate directly from English. Without context, how are people to guess the correct word?