That really doesn't describe London or Paris. Yes there was once an enclosed old city, there are some famous landmarks within it, but that enclosed old city is literally the skyscraper bank/finance-capital zone of London now. In Paris it doesn't exist because the city was and rebuilt by Napoleon. All the other features are mostly correct.

And London has a few nail houses, the problem with finding them is that nail house is not a popular term to use in the UK: https://www.indiatimes.com/trending/wtf/london-nail-house-wickham-spiegelhalters-566867.html