I'm surprised that an article on the use of negation in French forgot to mention anything about "si", an interjection used to negate a negative question. [1]
Example from Wiktionary: [2]
Tu ne m’aimes pas, n’est-ce pas ? — Si !
You don’t like me, do you? — Yes, I do!
Example from Wiktionary: [2]
[1]: https://french.stackexchange.com/questions/848/differences-b...[2]: https://en.wiktionary.org/wiki/si#Interjection