International travel @ 19 months old

Hello everyone. Going to try and keep this as anon as possible.

I will have a 19 month old during our december visit to see family in Nice, France from San Francisco, California. One layover in Paris. Returning straight from Paris to SFO.

This is about 22 hours of travel at least. Traveling with 3 other family members + my husband.

I don't even know where to start - I'm so lost. I traveled internationally a few years ago but never ever with a kid.

Any advice for ANY part of this trip is greatly appreciated. I'm so nervous my anxiety is going crazy