Liability: who pays if my son breaks something at a friend's house?

Basically, you're the one paying. Parents are legally responsible for damage caused by their minor children - it's in the civil code. So if your son breaks a vase, a mirror, or anything else at a friend's place, you have to cover the repair or replacement costs. That's where your liability comes in.

That said, it depends a bit on the situation. If it's just a stupid accident (he slips, boom, it's broken), well that's how it goes. But if you weren't watching your son and he deliberately causes damage, that could be even worse for you legally. The honest thing is to pay right away without dragging your feet - no need for the friend's parents to come after you. Most people sort it out amicably.

If you want to protect yourself a bit, check whether your household liability insurance covers this kind of thing. A lot of people have it included in their homeowner's insurance, and it can cover the damage. But without insurance, it's coming out of your own pocket.