If you travel with children in Europe you need to know that in case you are the only parent or adult taking a train or plane with your minor child or the minor child of a friend or family member, you should let the other parent or the parents fill out an authorisation form for travelling abroad with a minor.
All European countries have signed and accepted the The Hague Convention on the Civil Aspects of International Parental Child Abduction 1980. It is a “multilateral treaty, which seeks to protect children from the harmful effects of abduction and retention across international boundaries by providing a procedure to bring about their prompt return. The “Child Abduction Section” provides information about the operation of the Convention and the work of the Hague Conference in monitoring its implementation and promoting international co-operation in the area of child abduction.”
If you decide at some point to leave travel to another country with your child without the consent of your partner (i.e. the father/mother of your child(ren)), you may risk to be accused of abduction if you don’t fill in the form and if your partner doesn’t approve your travel. This also applies to adults who travel with minors that are not their children.
On the Government site of the Netherlands, you can find more information, or read my other post about this: