Hi,
there is a Monoprix supermarket between Le Louvre and Opera Garnier, 21 avenue de L'Opera, metro station is "Pyramides". You should be able to get milk and baby food, Nestle or Bledina. You'll find also mineral water anywhere.
FYI, I don't give cow milk to my baby boy (21 month yo) but "lait de croissance" as it contains vitamines, iron and whatever he is supposed to need.
Don't worry, French women don't always cook for their babies so there is plenty of choice available in the supermarkets.
Have a good stay.
10
mado67
Pro tip
