I went to watch French open last year with my colleague. After the event my friend took me to this nice little square called place de la contrescarpe, Sorbonne quarter of Paris if I am correct.
It is beautiful and lovely little cafe with nice cafes and bars with live music on the street.
We went for a stroll around after and bumped into Pantheon, a beautiful architectural building. It was a lovely evening abd I highly recommend this if you happen to be in Paris.
After all Paris is like a champagne bottle at night.
Have a great weekend.