I have a question about The Adventures of Tintin. Wikipedia says
Its well-researched plots straddle a variety of genres: swashbuckling adventures with elements of fantasy, [...]
But I'm not sure if there is enough fantasy to be on-topic here.
There's certainly a considerable amount of Fantasy (and even Sci-fi) involved in the various Tintin books. As with most "genre-based" stories, question about those elements are absolutely 100% on-topic.
Questions about non sci-fi or fantasy elements, however are probably off-topic as they would fall under general literature.
On-topic: What are the mysterious shooting stars in "The Shooting Star"?
Off-topic: What is Captain Haddock's favorite brand of whisky?
And as always, if you're in doubt you can always 'trial' the question out in the chatroom before posting it on the main site. You'll get a prompt response and plenty of feedback, I'm sure.