In Flanders you are paid a "startbedrag", a starting amount, for the birth or adoption of a child of €1,214.49. You can apply for the starting amount with one of the five Flemish payment funds of the Groeipakket.

This is the website of the Flemish government on the Groeipakket
Groeipakket:
Flemish child benefits and more
Every child in Flanders is entitled to a Groeipakket: a package of financial
benefits tailored to each child in each family. The Groeipakket varies from
child to child. The amount you receive depends on your specific situation.
In doing so, the Groeipakket (formerly known as kinderbijslag or
child benefits) contributes towards the cost of raising children.
Because each child deserves the chance to develop and reach their full
potential.
Recent news items
Applying for the Groeipakket
Did you already receive a starting amount for the birth or adoption of your child? Then you will automatically receive the monthly Groeipakket from the payment fund that paid your starting amount. In other cases (e.g. you are moving to Flanders) you can apply for the Groeipakket yourself from a Groeipakket payment fund of your choice.
There are five Flemish payment funds. You can switch payment fund after being a member for one year. If you choose a new payment fund, that choice applies to all the children in your family. You will then remain a member for at least one year.