"…The Occupying Power shall not deport or transfer parts of its own civilian population into the territory it occupies."

From the Israel Ministry of Foreign Affairs:
The provisions of the Geneva Convention regarding forced population transfer to occupied sovereign territory cannot be viewed as prohibiting the voluntary return of individuals to the towns and villages from which they, or their ancestors, had been ousted. Nor does it prohibit the movement of individuals to land which was not under the legitimate sovereignty of any state and which is not subject to private ownership. In this regard, Israeli settlements have been established only after an exhaustive investigation process, under the supervision of the Supreme Court of Israel, designed to ensure that no communities are established on private Arab land. It should be emphasised that the movement of individuals to the territory is entirely voluntary, while the settlements themselves are not intended to displace Arab inhabitants, nor do they do so in practice.