When you work in the catering industry (or 'Horeca' in Dutch) the chance is likely that the so called Horeca CAO (the collective labour agreement for the catering industry) has to be applied. This agreement states that employees who are a so called 'vakkracht' (skilled worker) must receive an extra allowance when they work on a public holiday. An employee becomes a 'vakkracht' when they've worked 1976 hours or more for the same company in the same job title. If this is the case, the employee has the right to receive this extra allowance of 50%. When the employee is not yet a 'vakkracht' it is not mandatory for an employer to give this extra allowance, but they can still choose to give this allowance to the employee anyway. Once the public holiday allowance is paid out, you can find this on your payslip behind the mention 'Feestdagentoeslag'.
According to the Horeca CAO New Year's Day, the First and Second Day of Eastern, Kingsday, Ascension Day, First and Second Day of Pentecost and Christmas Day and Boxing Day are public holidays. Also once in every 5 years Liberation Day is a public holiday.