Yes, the building is old--it's France, buildings are old. That's why we love them!
The apartment is bright, spacious, sunny, and has the most amazing views of Lyon. Everything works fine (though we were uncertain how to work the dishwasher and stove, this seems pretty common in Airbnbs, which have all kinds of appliances). Yes, there are many stairs and hills--it's Lyon!--and while the street itself is quite steep, you can in fact catch a Metro from the center of town that will get you above the street so you can actually walk down instead of up to the building. There are also buses nearby.
Annick (a neighbor) checked us in, was very kind and helpful; all communication clear and quick. Shower worked beautifully. We had a very comfortable two nights, and my daughter and her boyfriend were easily able to watch the final World Cup game on TV.