This is the Bohéme pattern for babies from size 6 to 24 months, knitted in a thinner yarn than the pattern for kids and adults.

Finished sizes for Baby Bohéme Sweater
Size 6 months: Length 30 cm. Chest: 48 cm. (19”).
Size 12 months: Length 33 cm. Chest: 52 cm. ( 21“).
Size 18 months: Length 36 cm. Chest: 55 cm. (22”).
Size 24 months: Length 38 cm. Chest: 58 cm. (23”).

Yarn requirements for the baby sweater
Size 6 months and 12 months:
100 g of base colour and 30 g of contrast colour.
Size 18 and 24 months:
150 g of base colour and 50g of contrast colour.

Needle sizes: 3 and 3.5 mm (US 3 and 4)