Charlie was amazing. Everything was as described and even checked if we were happy to go up to the 6th floor before booking, and everything else before our arrival. Knowing it was my birthday, he even placed a complimentary bottle of Bordeaux (very thoughtful).
The location is great, especially if taking the Eurostar. We arrived very late and left very early, and walking was no problem, even late at night. It's also within walking distance of several metro stations (check a map). Charlie also left us a key in a secure locker.
The actual flat is very small but cute. It has all you could possibly need. I will say, the walk up is not for the faint of heart, but for us is was just an incentive not to forget anything before going down. The toilet was shared (not sure with how many), but it was always clean and tidy (even though the little closet looks old), so no reason for concern there. Lastly, it felt safe, as there are two code-protected doors before the studio door, which has a good lock.
In conclusion, it's a small but efficient and excellent space. Really fantastic value. The host is kind and responsive, as well as thoughtful, friendly and approachable.
Would definitely recommend and stay again.