People's belongings or peoples' belongings? [closed]

Solution 1:

People as a plural of person is a mass noun, and we don;t use a plural -s. So when forming a possessive, we only add the 's:

I refuse to look after other people's belongings.

However, people can also be countable, when we refer to a(n ethic) group of persons: the Belgian people, the British people. Although a bit contrived, you could be referring to belongings that are the property of such groups.

For example:

The artwork from the Acropolis belong to the Greek people. Some of them are now in the British museum, but I don't see why they should look after other peoples' belongings.