Wonderful hosts, we had to check in late in the night (10 pm). They were very flexible about it and waited for us, even helped me with my wife heavy luggage.
The place is nice just as the pictures, it is actually smaller than we thought but that's should be paris way and considering it is a studio. Balcony was good for a drink and smoke, enjoying the view to the street, place was super clean with all you need. However, space shouldn't be a problem as visiting Paris takes all day and you only get there to sleep and shower. It is good for two people.
Mind your luggage, like all the reviews said it is on the fifth floor and it's a tall building, so expect lot of stairs. Just for people who mind that or are planing to carry a lot.
Location is very convenient as you have connections to RER, metro and trains within minutes. It is not the most beautiful neighborhood in Paris but that's like every neighborhood close to train stations in every country. But is safe to walk on nights.
Definitely consider it for staying if you don't want to have any issues with transportation and want easy connections to get in and out of the city, plus Patrick and frank are very nice and would give you good recommendations !