Real estate law refers to the creation, content, change and cessation of the ownership right to real estate and other property rights to real estate, such as perpetual usufruct, usufruct, land easements – these rights are absolute rights, i.e. effective erga omnes – for everyone. The opposite of the aforementioned rights are obligations concerning property that are effective only with respect to parties to the agreement, for example contracts concerning real estate lease, tenancy and lending.