Most importantly Marc is a brilliant host. He is really kind and generous. He goes out of his way to make your stay comfortable: clear instructions, offering to store luggage, plus he's easy to contact.
The apartment is absolutely beautiful in a classic Parisian building with lots of character. The location is great - you can easily walk to the Louvre and there are many public transport options including lots of buses and two metro stations nearby.
It's clean and organised with a good quality sofa bed. I slept well on the large sofa bed and it's really quiet at night despite being so central.
This is the perfect studio flat in Paris and I would love to stay here again.