Matilda is a book by Roald Dahl, it's also translated to French.
May I ask, which delf/dalf level is this French version Matilda equivalent to? of course, I'm referring to reading, not about listening, speaking, etc.
This seems somewhat subjective because I was not able to find a formal classification of the book online. I'm assuming you're referring to Henri Robillot's translation. The book is often suggested to French students in 4th/5th grade (American System) which would be CM1/CM2 in France (based on past experience and a quick internet search). This would mean it's a DELF Prim level, more towards A2.