[en] The incident analyses performed in French nuclear power plants high-lighted that deficiencies in the design of procedures are frequent causes of human errors. The process for developing new guidelines for the writing of test and emergency procedures is presented: this process is based on operators interviews and observations at the plants or at simulators. The main principles for the writing of procedures are developed. For example: - the elaboration of a procedure for action and of a separate educational procedure, - the coordination of crew responses, - the choice of vocabulary, graphs, flow charts and so on as regards the format. Other complementary actions, such as the training of operators in the use of procedures, are described