Heatwave at Work 2026: Employer Responsibilities, Legal Duties and Prevention Measures

Summer 2026 is not just another summer for French employers. Légifrance states that this is the first full season under Decree No. 2025-482 of 27 May 2025, which wrote the prevention of intense-heat risks directly into the French Labour Code. What used to be a recommendation has become an enforceable regulatory obligation — and it is being enforced.

As reported by Prévention BTP, summer 2025 saw nine fatal workplace accidents potentially linked to heat reported to the Directorate General for Labour, mainly in construction and agriculture. The labour inspectorate responded by carrying out more than 1,600 inspections during the first heat episodes, with around 10% resulting in a formal notice.

This guide details employer obligations during heatwaves at work in 2026, vigilance level by vigilance level, with a focus on construction sites and a practical method for building your company heatwave plan.

Key point: there is still no legal maximum temperature above which work automatically stops. The legal trigger is now the colour of the Météo-France vigilance alert — and obligations begin at yellow.

Météo-France Vigilance: The New Legal Trigger

Under the changes described by Code du travail numérique, the Labour Code now defines an "intense heat episode" by direct reference to Météo-France's heatwave vigilance system, representing the key conceptual shift introduced by the 2025 decree. Three levels trigger obligations:

• Yellow vigilance: heat peak or persistent heat episode — prevention obligations activate

• Orange vigilance: heatwave — reinforced obligations and daily risk reassessment

• Red vigilance: extreme heatwave — immediate measures, up to and including suspending exposed work

Green vigilance does not constitute an intense heat episode. In practice, this means a manager or HSE officer must build the vigilance map into their daily summer routine, just like any other operational indicator. The mechanism applies indoors as well as outdoors: a non-air-conditioned warehouse or a restaurant kitchen is covered just as much as a construction site.

What Employers Must Do from Yellow Vigilance Onwards

Under Article L4121-1 of the Labour Code, employers must take all necessary measures to protect employees' physical and mental health. As explained by economie.gouv.fr, this general safety obligation remains the foundation of workplace health and safety requirements. The 2025 decree translates this principle into concrete measures, codified in Articles R4463-1 to R4463-8, applicable whenever an intense heat episode occurs.

The measures employers must implement include:

• Adapting work organization, particularly working hours (early morning starts, suspension of strenuous tasks during the hottest hours, extended breaks)

• Modifying workstation layout: blinds, sun shields, ventilation, misting systems, shaded areas

• Prioritizing work processes that do not require heat exposure, or require less of it

• Increasing the supply of cool drinking water, with a means of keeping it cool throughout the day close to workstations

• Providing suitable equipment: PPE and workwear compatible with high temperatures and protecting against solar radiation

• Informing and training employees on what to do during extreme heat

• Establishing a rapid alert and rescue procedure, with heightened vigilance for isolated workers

This entire assessment must be recorded in the DUERP (the single occupational risk assessment document) under thermal environment risks and communicated to the works council (CSE), according to CCI Paris Île-de-France. A DUERP that is silent on heat risk is now one of the first things labour inspectors check.

Orange and Red Vigilance: Daily Reassessment Becomes Mandatory

From orange vigilance onwards, the regime changes in nature. economie.gouv.fr notes that employers should reassess heat-related risks every day by considering the day's temperature trends, the type of work involved, and each employee's age and health status.

Based on this reassessment, workload, schedules and work organization more broadly must be adjusted for the entire duration of the episode. Prévention BTP explains that under red vigilance, work must be suspended if preventive measures are no longer enough to ensure safety. It also reports that, in 2026, several departments issued prefectoral orders prohibiting outdoor work during the hottest hours, with construction sites shifting their start times to 5 or 6 a.m.

The logic of the regulation is graduated: the higher the vigilance level, the less discretion the employer has. Under red, the question is no longer "how do we keep working?" but "can we work safely?" — and the burden of proof falls on the company.

Heatwaves on Construction Sites: The Sector-Specific Rules

The construction sector combines the general rules with its own regime. According to  Prévention BTP, employers operating sites without running water must comply with Article R4534-143 of the Labour Code by supplying each worker with at least 3 litres of cool drinking water per day. Added to this are rest areas adapted to high temperatures and verification that PPE remains wearable in the heat — hot weather never exempts anyone from helmets or safety shoes.

The other pillar of the construction framework is financial. Since Decree No. 2024-630 of 28 June 2024, heatwaves are officially recognized as adverse weather ("intempéries"), on the same footing as frost or snow. As reported by FFB, a site shutdown during the seasonal watch period (1 June–15 September) in a department under orange or red vigilance, or covered by a prefectoral order, gives companies access to compensation under the CIBTP weather-related unemployment scheme,

A 2026 development: given how early the heat arrived, CIBTP France exceptionally opened coverage for heatwave-related shutdowns from 26 May 2026 for departments covered by prefectoral orders, ahead of the official start of the seasonal watch. For a site manager, the reflex is therefore twofold: secure the teams first, then document the shutdown and its justification to secure the compensation.

Right to Withdraw and Vulnerable Workers: What Teams Can Demand

According to Code du travail numérique, heat alone is not enough to automatically trigger the right to withdraw from work. Under Article L4131-1, employees must have reasonable grounds to believe their situation presents a serious and imminent danger to their life or health, assessed case by case based on factors such as heat intensity, the nature of the work, health status, duration of exposure, and the employer's preventive measures. An employer who properly applies the decree therefore mechanically narrows the grounds for withdrawal.

Certain groups require particular attention. As highlighted by Le Club des Juristes, employers must not assign workers under 18 to tasks exposing them to temperatures of 30°C or higher and should implement specific measures for pregnant employees, workers with chronic conditions, and isolated workers. The occupational physician and the CSE are the two stakeholders to involve systematically in these decisions.

Building Your Company Heatwave Plan: The 6-Step Method

An effective company heatwave plan cannot be improvised when the first orange alert lands. Here is the approach applicable to any organization, from micro-businesses to large groups.

Step 1 — Assess and record heat risk in the DUERP. Review every position, indoors and outdoors, and document thermal exposure: this is the legal foundation for everything else.

Step 2 — Appoint a lead and organize weather monitoring. One person (HR, HSE, site manager) checks the Météo-France vigilance level daily during the season and triggers the measures tied to each colour.

Step 3 — Prepare material measures before summer. Cool water and means of keeping it cool, ventilation, blinds, shaded areas, misters: everything must be operational before the first episode, not on order during it.

Step 4 — Formalize adaptation scenarios per vigilance level. Shifted hours, rotation of strenuous tasks, reinforced breaks, suspension thresholds: write down who decides what, at which level, and communicate it to the teams.

Step 5 — Train employees and supervisors. Everyone must be able to recognize the signs of heatstroke (headaches, cramps, nausea, disorientation) and know the response: move to shade, cool down, call 15 or 112.

Step 6 — Document and reassess. Under orange or red vigilance, record the daily risk reassessment and the decisions taken: this paper trail is your best protection in the event of an inspection or accident.

What Employers Risk by Doing Nothing

The labour inspectorate can issue a formal notice requiring the employer to comply with heat-risk prevention obligations — a notice which, if not acted upon, leads to an official report according to Code du travail numérique. Beyond the administrative side, a heat-related accident can engage the employer's liability for inexcusable fault, with heavy financial and criminal consequences.

The equation is simple: the required measures (water, shade, adjusted hours, breaks, training) cost little; a fatal heatstroke at a workstation costs everything. Compliance with the 2025 decree is not only a legal issue — it is a marker of prevention culture that your employees, clients and contracting authorities all notice.