Is it legal for a parent to confiscate items from their child who is over 18?

Question

Can a parent legally confiscate items (e.g. electronic devices) from a child who is over 18 years old?

Answer 1

france

In France, there cannot be any theft between children and their parents (or between two spouses). It's not that the parents are allowed to confiscate things, there is a blanket immunity from criminal prosecution in article 311-12 of the Code pénal, in both directions (parents to child but also child to parent). The underlying logic is that this is something families should sort out between themselves, not through the justice system.

There is however a recently added exception to this long-standing principle: You are not allowed to remove “things that are indispensable to day-to-day life like ID documents […] means of payment or telecommunication”. So basically, taking away your adult child's mobile phone is very likely to be prosecutable as theft, a cooking or self-care appliance, probably not. The exception for ID and means of payment was added in 2006, the reference to “means of telecommunication” in 2015. (There are other caveats not relevant to this question, e.g. for married couples who are legally separated).

Interestingly, it's the exact opposite of the principle described in Dale's answer: This is based entirely on the family relationship, whether the adult child lives together with his or her parents or, say, get financial assistance from them doesn't matter.

Answer 2

Not based on just the parent-child relationship

However, if the child is a guest in the parents’ home, the parents can impose conditions - implicit or explicit - on the child continuing to be welcome there.