Hello

I am going to have this Saturday in Paris by myself. I have only ever been there once, a long time ago, and spent a couple of hours at the Rodin museum. So, I just wondered if any of you know the city and have any recommendations how I can amuse myself for the day? weather supposed to be boiling hot so not sure I want to spend too long out in the sun (can't control the tan lines when I am in public!!!). there are so many things I could do that some personal recommendations would be much appreciated