What is occupation?
from the International Committee of the Red Cross (emphasis added)
Territory is considered occupied when it is placed under the authority of the hostile army. The occupation extends only to the territory where this authority has been established and can be exercised. The law on occupation applies to all cases of partial or total occupation, even if such occupation does not encounter armed resistance.
The essential ingredient for applicability of the law of occupation is therefore the actual control exercised by the occupying forces. Occupation ceases when the occupying forces are driven out of or evacuate the territory.
The civilian population of an occupied territory owes no allegiance to the occupying power. It cannot be forced to fight its own country, be involved in any way with the armed forces or give military assistance to the occupying power. Civilians are at all times entitled to respect for their persons, honor, family rights, religious convictions, and manners and customs. Their private property is protected.
Any discrimination for reasons of race, nationality, language, religious convictions and practices, political opinion, social origin or position or similar consideration is unlawful.
The occupying power may only put in place such measures of control and security as may be necessary as a result of the conflict. Collective penalties, measures of intimidation, terrorism and hostage-taking are prohibited.
Individual or mass forcible transfers and deportations of the civilian population from occupied territory are prohibited.
Specific areas may be temporarily evacuated if warranted by the security of the population or imperative military necessity. Generally speaking, the population may not be evacuated to locations outside the occupied territory, again unless this is the only option available. In that case, the evacuees must be returned to their homes as soon as the security situation allows.
The occupying power must not deport or transfer parts of its own civilian population into the territory it occupies.