lait

In most French supermarkets, you can get fresh milk in the dairy section or UHT milk on the shelf, where there is quite a wide choice of milks to choose from (low or no lactose, fortified with extra vitamins, etc.)

lait entier: full fat milk (red cap on the bottle)

demi-écrémé: half skimmed milk (1.5% or 1.8% fat, blue cap on the bottle). This is the most common in France.

écrémé: completely skimmed (green cap on the bottle)

Some other useful milk words:

babeurre: buttermilk

confiture de lait: dulce de leche

lait au chocolat: chocolate milk. Cacolac, a popular commercial version sold in bottles, has been made in Bordeaux since 1954.