A day and a half in Paris

Hello,
I am traveling to London and will be taking the train to Paris on Wed 2nd April at 5:40 and returning to London on Thursday 3rd April on the 12:36 train.
Can anyone give me a few ideas on the best way to spend my time in Paris or let me know if you are available to meet? I'm really excited and looking forward to having a fun time.
I am also looking for a good inexpensive hotel to stay at for the night.
Thanks in advance for any help you can provide for me.