Social public housing offer rents that are more than 60 % undervalued. The total `loss' of public sector landlords amounts to 37 billions Francs per year. The `rebate' allows social sector tenants to consume 10 % more housing services and 11 % more of other goods. The surplus gain of living in the public sector is about 34 billions Francs. Housing allowances represent half this amount for the same tenants and are more concentrated on the poorest population, because some high income households live in the social sector. The surplus loss for the collectivity due to these transfers is 3 billions Francs per year, 8 % of the transferred sums.