Vote 2 for Janet's suggestion of the cafe there,lol.
Also, this is a free museum although there is a charge if they have a special exhibition. If there is something special on view, by all means pay to see it even if you are not sure who the artist is, lol. In October I went to a special exhibition on a Swedish artist, Bruno Liljefors with whom I was not familiar. It was outstanding and now I have a new artist whom I enjoy! Previously I went to an exhibition about Sarah Bernhardt with a bunch of posters by Mucha which was also outstanding. It was well worth the 10E or so to visit. I did not buy ahead, just purchased at the desk on entry.
There is a Petit Palais app which I have and which is pretty good. The audio is in French but there is translated audio as well as translated written text so you can do either. It's free, of course and well worth downloading.
I've been in a number of times and honestly, I guess I never had made it to the ground floor until this last visit. I finished the Liljefors exhibition which was on the ground floor and just continued around and saw things I'd not seen there before. They have a wide ranging collection from Rembrandt to Monet.
Since it is a City of Paris Museum it's closed on Mondays.