And what " peremptory norm of general international law " does Oslo conflict with. Give the law and its date of implementation and how Oslo applies ?
Civilians are at all times entitled to respect for their persons, honour,
family rights, religious convictions, and manners and customs. Their
private property is protected.
The civilian population is in a tense and vulnerable position. The law
states that it must be humanely treated in all circumstances and pro-
tected from any acts of violence, including by third parties. 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.
The legal rights of the inhabitants of occupied territory cannot be curtailed
by any agreement or other arrangement between the occupying power
and the authorities of the occupied territory. This is intended to prevent
national authorities from being put under pressure to make conces-
sions which might not be in the population’s best interests or weaken
its legal rights.
Similarly, the inhabitants of the occupied territory cannot renounce their
rights under the Fourth Geneva Convention. This again is a safeguard.
It prevents the occupying power from exploiting the vulnerability of the
occupied territory by exerting undue pressure to undermine and weaken
the protection which the law affords.
Individual or mass forcible transfers and deportations of the civilian
population from occupied territory are prohibited.
The occupying power must not deport or transfer parts of its own civilian
population into the territory it occupies.
Destruction of property.
The occupying power is not allowed to destroy real or personal property belonging individually or collectively to private persons, to the State, to other public authorities or to social or co-operative organizations, except where such destruction is made absolutely necessary by military operations.
https://www.icrc.org/eng/assets/files/other/law9_final.pdf