For unfurnished leases constituting the tenant 's principal residence: if the tenant does not spontaneously revise the rent on the date agreed upon in the lease, the lessor must manifest his willingness to revise the rent within a period of one year; this revision of the rent takes effect as of his request.

If the lessor does not express his will to apply the rent revision within one year following the effective date of this revision, he is deemed to have renounced the benefit of this clause for the past year.