The rent capping policy was implemented by the loi ALUR, which took effect from August 1st, 2015.
A new prefectoral decree sets new rent benchmarks based on geographical zones, which remain unchanged, despite a certain degree of inconsistency (see the article – in french – Encadrement des loyers : une loi attendue, mais décevante… pour tous).
These new rent benchmarks take effect in Paris on August 1st, 2016, for furnished and unfurnished accommodation rented as the tenant’s primary residence. Compared to a year ago, the rising and falling rent benchmarks have kept quite stable: some have increased a little while others have fallen slightly, but the majority remain unchanged (you can see the decree and full details of the latest rent benchmarks sorted by area here: http://www.drihl.ile-de-france.developpement-durable.gouv.fr/IMG/pdf/recueil-idf-033-2016-06-raa-special-pdf_cle076ba9.pdf)
There is also an interactive map available on the site for the Regional and Interdepartmental Board for Housing and Accommodation (DRIHL), which lets you view rental costs based on accommodation type (number of rooms, furnished and unfurnished, period of building, etc.), neighborhood and address. To see this, click here.