We need to go from Paris to Côte d'Azur in September. Any advice?
1) Where in the Côte d'Azur?
2) Look up times and prices on your favourite rail website (e.g. SNCF).
3) Book early for cheap prices.
Lots of info about trains in France here: https://seat61.com/France-trains.htm
Was there anything else specifically you want to know?
You get also fly from Paris ORY or CDG to Nice NCE.
Its up to you.