I had a great stay in Mickael's flat for long work trip! His father met me when after I arrived from the airport. He kindly helped me with my luggage and showed me the basics of the apartment.
The apartment is beautifully decorated with lots of cool art pieces and furniture. The kitchen had most of the amenities you would need and I got to cook a lot of good meals (roasts/etc).
The only cons were:
There isn't a full length mirror, but I would go to the elevator area and check myself out there either in the reflection of the elevator door or in the elevator itself.
There wasn't a whole lot of space for the 5 weeks worth of clothes I brought, but I made do with the makeshift hanging area and shelves/suitcase.
If these things don't bother you, I highly recommend this apartment. Super close to the Eiffel Tower, a 5 min walk to the 6-metro line or 9-metro line. It's also a stone's throw away from Rue Passy where there are tons of upscale clothing stores, banks, cafes, a couple of great boulangeries, two Monoprix's (the farther one is better), and a lovely (pricey) farmer's market.
I slept super well in the comfy bed, loved the lighting, and felt completely at home. It became my haven from the world!