In France, a couple earning the minimum wage and a couple of well-off executives can live in the same type of apartment, in the same city, paying nearly the same rent per square meter. Yet one spends almost half of their budget on housing, while the other spends barely a tenth. This large difference in housing costs, far from being a statistical oddity, silently shapes the lives of millions of French people. As the school year begins, when fixed costs weigh more than ever on household budgets, it is time to understand what is really behind these staggering figures. According to data from INSEE, the French national statistics office, the 20 percent of the most modest households allocate nearly 40 percent of their income to housing, compared to only 8 percent for the 20 percent most affluent. This ratio of one to five highlights housing as the first invisible inequality of daily life. This disparity is not limited to a few isolated cases but affects millions of households across the country. Other statistical breakdowns confirm the trend, showing that the 25 percent most modest allocate around 32 to 34 percent of their income to housing, compared to 14 to 16 percent for the 25 percent most affluent. For the 10 percent poorest, the effort rate even rises to 42 percent, four times that of the 10 percent richest. When considering housing assistance, some modest private sector renters show an average net effort rate of 44.7 percent, compared to only 7.1 percent for affluent non-homeowners. These figures reveal a growing problem that has been worsening over time. The most common assumption is that the price per square meter or the size of the apartment is the main factor behind this gap. However, this is largely insufficient. The real explanatory factor lies in the occupancy status of the housing. Among modest households, being a homeowner or a private sector renter radically changes the situation: homeowners among this group allocate 18.7 percent of their income to housing, compared to 40.7 percent when they are private sector renters. In other words, it is not so much the size of the apartment or even the absolute amount of rent that burdens the budget, but rather the fact of not owning one's home. A homeowner, even a modest one, has finished repaying their property or has only a minor remaining loan, while a renter indefinitely pays an amount that builds no wealth. Social housing partially corrects this mechanism: it allows modest households to bring the share of the budget allocated to housing down to an average of 27.3 percent, a figure much lower than that of the private sector, without completely eliminating the gap with homeowners. For modest households, rent, charges, home insurance, and energy bills form an incompressible block of expenses that impose themselves even before thinking about food or leisure. For affluent households, this same block of expenses represents a marginal part of a much larger income, leaving a considerable margin for maneuver. This logic explains why one in five private sector renters spends more than 40 percent of their income on housing—not necessarily because their rent is exorbitant, but because their overall income is too low to absorb a fixed cost that remains the same regardless of the standard of living.