Sale price of old houses in the largest French cities 2020

The source adds the following information:
"The median price is such that 50% of the transactions were concluded at a lower price and as much at a higher price. It represents the "middle" of the market, better than average, more sensitive to extreme values. The prices in Île-de-France are a valuation of the INSEE-INSEE indexes for the 1st quarter of 2020."
"The method of calculating the Notaires-INSEE indices is based on econometric models that break down the price of a house according to its main characteristics (location, size, comfort, etc.) so as to be as free as possible from structural effects that could cause transaction prices to vary from one quarter to the next."