The EU and the IMO are working to harmonise and improve the rules for design and build of merchant ships. The immunity given to warships spares them from the burden of this set of standardising rules and regulations, which do not take into account their technical and operational peculiarities. Given the wealth of feedback from the world’s merchant fleets, some of these technical recommendations could nevertheless prove to be beneficial to warships. As a consequence of the change in status of the DCN, the French Navy is increasingly calling upon civil shipbuilding yards and classification companies, and is looking seriously at closer similarity between warship build standards and those for methodology and design applicable to the merchant navy.