This index is composed of two indices:

• The Notaires-Insee price index for old homes is calculated by Min.not and Paris Notaires Services (PNS) in collaboration with INSEE from the real estate transaction data contained in the notarial databases;

• The new housing price index is calculated by INSEE using data from the survey on the marketing of new housing (ECLN).

The Notaries-Insee index of prices of old houses provides a measure of price trends of old houses of constant quality. The price retained is the net selling price, excluding transfer duties, notary fees and agency commission.

The new housing price index provides a measure of new housing price developments at constant quality. The price retained is the price at the reservation, i.e. at the signature of the first contract. VAT is included in this price. Notary fees are not.

For a given quarter, the housing price index is obtained by weighted average of the two new and old housing indices.

The IPL is a transaction price index measuring, between two consecutive quarters, the pure evolution of house prices sold.

The second-hand dwellings considered are those belonging to the field of the Notaires-INSEE index (excluding overseas departments) i.e. housing older than 5 years or undergoing a second mutation.

The new dwellings retained are those belonging to the scope of the new housing marketing survey (ECLN). It covers permits of 5 units or more for sale to individuals.