Housing vacancy in France represents 8.3% of the dwelling stock, a constantly rising rate since the 2008 crisis. This statement is less and less socially accepted in a time where urban spreading is meant to be stopped for ecological reasons, so that fewer new buildings can be produced and the remobilization of empty housing seems to be necessary to reach the European target of “zero net land take”. Empty houses are also morally unacceptable against the background of 4 million people (6% of the population) that are poorly housed – 330,000 of them being homeless (2023). This gave rise to a national program of “fight against housing vacancy” (2018), which has tried to develop incentive and coercive (fiscal) tools against this problem – but with few results. This paper would like to understand the reasons why the objectives are so difficult to reach. First of all, the problem is probably poorly defined: the vacancy criterion is a fragile indicator that groups together contradictory situations. Not all vacant housing is available: a majority of the considered stock is a “frictional market vacancy”, and its growth reflects above all the positive dynamics of real estate transactions. Very few empty dwellings are the result of a speculative vacancy or even of a lack of interest on the part of negligent owners. On the other hand, the association between 3 million vacant units and 3 million people to be housed is abusive, because this observation forgets the segmented nature of the real estate markets: the location of needs does not meet at all the demand, and the vacancy also reflects very depreciated properties that do not fit with the basic expectations of potential buyers. A cartographic exploration of the problem reveals a strong urban/rural divide in France in this matter. Finally, the program of “fight against housing vacancy” has identified a priority objective of supporting renovation in the town centers of small cities, where price opportunities and public facilities are attractive. However, employment conditions and the supply of commercial services are generally prohibitive and require a much more cross-cutting approach to land use planning.