12 m² room in Paris

A room has opened up in our 64 m² flatshare in Noisy-le-Sec, a 6-minute walk from the RER E. The apartment is on the 3rd floor with no elevator. The rent is €365. Utilities/charges are €70 (gas, electricity, internet, insurance). There are two options for renting: either subletting from the third person who is on the lease but who is not eligible for APL (housing assistance), or making an addendum to the lease (which prevents the landlord from raising the rent, avoids paying real estate agency fees, and allows receiving APL). The addendum ...