The Employee gets a tax reduction for every child upto 25 years living in Germany regardless of the Nationality.
But this reduction influences only Solidarity Surcharge and the amount of Church Tax. This is because the possible reduction of the taxable income is already compensated by the Child benefit.
You will get Child Benefit/KinderGeld Form from ‘Arbeitsagentur’ website.
Child Benefits (living in Germany):
Parents get 2.208 €/year for first and second child
Parents get 2.280 €/year for the third child
Parents get 2.580 €/year for the fourth child on..
You can find monthly net salary using this calculator