Provided further that nothing in this section shall apply to any periodical increment of rent accruing under any subsisting agreement entered into before the first day of January, 1939.

Landlord not to claim in excess of fair rent

1. (1) Save as provided in section 5, when the Controller has fixed the fair rent of a building or rented land under section 4—
   • (a) the landlord shall not claim or receive any premium or other like sum in addition to fair rent or any rent in excess of such fair rent, but the landlord may stipulate for and receive in advance an amount not exceeding one month's rent ;
   • (b) any agreement for the payment of any sum in addition to rent or of rent in excess of such fair rent shall be null and void.
2. (2) Nothing in this section shall apply to the recovery of any rent which became due before the 1st day of January, 1939.