The location is perfect for staying in Le Marais. You are right in the middle with lots of trendy shops, bars, cafe and places to eat.
Just as the pictures, the room is small. Fine for one person and ok for two if you are ok with confined spaces. The central heating was great (was snowing while we stayed), but room was very warm. One wall looked like it was being treated for mould, but no smell so fine. Just needed to be painted white to match the rest of the flat.
The flat is up two floors of stairs with no lift. This added to the character of the building, but bare-in-mind if lots of luggage or trouble with stairs.
There is a small fridge (extremely cold), plates, cutlery to use. A plug in stove if needed, but I would suggest if you need a kitchen while staying, this flat is not the one. There are great places to eat in the area, bring money as all very expensive.
My only negative is the temperature of the shower water if you like a warm/hot shower. The water got warm for a quick dash in the shower.
Tips for the area; Le Perla bar for the fashion crowd and good priced drinks, La Pick Clops for food. Wine at La Belle Hortense. Morning pastries and sandwiches (have breakfast here too) Boulangerie de Rennes... Delicious!