Heat wave : Cold sweat in perspective for the employer

The Ministry of Labour has published the National Heat Wave Plan (in French: Plan National Canicule (PNC)) and put online the ministerial instruction oft he 11th of Juin 2018 about the rules of labor law on this subject.
These texts specify that it is up to the employer to ensure the implementation of measures in order to limit the effect of a heat wave on the employees, and, this in the context of the obligation to protect the health of employees. What are the concrete rules that must scrupulously complied with by the employer?