The Residhotel is recognized as good for long stays, and that certainly matched my experience. The room includes a small kitchen area that allows someone to have snacks or meals at the hotel. The hotel is well located. You have a short walk to one Metro station, and a slightly longer walk to other Metro stations and RER. And if you want the shuttle to Beauvais (for Ryanair) that station is a 20 min. walk.
Also, you have two laundries nearby, and a variety of small to large grocery stores.
There are plenty of options nearby for eating, coffee, drinks.
The Arc de Triomphe is an easy walk from the hotel, and the hotel location allows you to go to most of the important sites within a half hour (on foot and by Metro).
The facility itself is clean. I was very comfortable there. The staff there were very helpful to me, with the front desk people making it their job to work out any issues I had.
I'd have to agree with one of the other reviews that the facility is showing its age. There were no real problems as far as I was concerned, but some updates to furniture and appliances would make the rooms might be in order.