New Year's Eve in Paris

The drinking age is 18 over there anyway compared to 21 here,
You should narrow it down. What kind of music or entertainment do you and your family like?
Then depending on the venue you will get idea what to wear.
For example I've spent 2015 and 2016 ringing the new year in Paris at Sunrise Sunset Jazz Club with other jazz lovers from all over the world, It is not for everyone but I love the atmosphere there. Last year a rung in the New Year at a Flamenco Club in Seville, Spain, But I love Flamenco.

What is your budget? Hard to make suggestions for where to reserve without knowing how much you want to spend. Also, do you want dinner or a show of some sort? If you want dinner and champagne and the sky is the limit or least the sky for me at around ~500€ per person, make reservations at Le Cinq at Hotel George V or at either of the restaurants at Hotel Bristol. For a show, maybe hit one of the cabarets. I've never been to a cabaret but I've heard that the NYE show at the Lido is good. There are street parties in a few locations in town and maybe a light show on the Champs Elysees -- no need for reservations.

I don't know what is planned for 2019 NYE but traditionally there is not a fireworks display in Paris for New Year's Eve. The big fireworks day is July 14. when we were there NYE there were a few randos shooting bottle rockets here and there. and a little bit of lame 'light show' on the Tower, but no impressive fireworks.

The New Years Eve firewortks myth is one of the most persistant myths of the internet - one did happen in 2000, and various websites have been promoting it ever since. You may also find French people resistant to hugging or kissing strangers, even on New Year's Eve.

If, however, you want to witness the New Years tradition of car burning, there are plenty of places...

Take a puffy coat and a hat.

My experience is that strangers are happy to maul young women on NYE -- my son and I had to rescue my daughter from this delight. But no fireworks. So before planning on that at least do some research to see if anything is planned this year. It would be unusual if it is happening.

I was in Paris New Year's Eve 2013. It rained cats and dogs and was freezing cold. But, I loved every minute of it. Enjoy whatever you do, pack an umbrella and warm clothes for layering.