Coping with natural hazards induces a social re-organization. Threat acceptance and the acceptability of technical solutions to reduce seismic vulnerability are linked to knowledge of the hazard and the willingness of the constraint. In France, the importance of state managed defense about natural disasters skips more interrogation about social acceptance of it. Anti-seismic technologies in housing impose a zoning of seismic hazard to graduate architectural constraints according to the probability of shakes. The new probabilistic zoning gives opportunity to examine the spirit and the scientific matrix to understand the choices of experts and public authorities. In opposition, the REVDOU sociological survey developed in 2011 at Salon de Provence, Albertville, Mulhouse and Tarbes cities about the engagement of owners, builders and administrations in anti-seismic technologies shows the variation of risk acceptability according to the local social consensus about acceptable organization and inacceptable threat. These four situations of moderate seismic exposition illustrate how some changes in the seismic zonation and building codes oblige local actors to appreciate the modalities of common control and the definition of the solidity of buildings. The study shows the gap between probabilistic concepts of hazard incorporated in the rule and local acceptability of seismic threat and professional constraints to reduce some invisible threat.