A memo announcing a change in working hours should not be drafted in the same way depending on whether the employee is full-time, part-time, or subject to specific contractual constraints. The memo template for changing hours must therefore incorporate legal variables that many standard documents overlook. Comparing situations allows for the selection of the appropriate wording and helps avoid disputes.
Change of hours: what is covered by the contract and what is not
The fundamental distinction can be summarized in one line: modifying the hourly distribution of a part-time employee affects the contract, not just a simple adjustment of working conditions. For a full-time employee subject to collective hours, changing a shift from 8am-4pm to 9am-5pm generally falls under the employer’s authority.
In contrast, for a part-time employee, changes to the distribution of hours are governed by the contract and by notice periods defined by law or collective agreements. A memo cannot therefore impose this type of modification without prior verification.
| Situation | Legal Nature | Is a memo sufficient? |
|---|---|---|
| Full-time, shift change of collective hours | Change of working conditions | Yes, unless there is a contrary contractual clause |
| Part-time, new distribution | Modification of the contract | No, employee’s agreement required |
| Change from day hours to night hours | Modification of the contract | No, employee’s agreement required |
| Temporary adjustment for high temperatures | Preventive measure (safety obligation) | Yes, within the framework of the employer’s authority |
This table shows that a single model does not fit all configurations. Before distributing the memo, it is essential to identify which column the proposed change falls under. A complete example of a memo on Info Manager details the structure suitable for each scenario.
Mandatory mentions in a memo about working hours
The legal value of a memo depends directly on its content. Omitting a mention makes the document contestable. Here are the elements that each memo must include to be enforceable.
- Effective date and duration: the exact day the new hours come into effect and, if applicable, the end date if the change is temporary (heatwave, seasonal peak activity).
- New hours detailed by day of the week, indicating the lunch break and the unchanged weekly hours.
- Reason for the change: reorganization of the department, safety obligation related to weather conditions, adaptation to workload. The reason legitimizes the use of the employer’s authority.
- Identity and title of the signatory: the document must be signed by a person with managerial authority (manager, human resources director, establishment manager).
- Method of distribution and date of delivery: posting, hand delivery, sending by email with acknowledgment of receipt. The notice period must comply with the applicable collective agreement.
The absence of the reason is the most common mistake. Without justification, the employee can argue that the change is arbitrary, which weakens the employer’s position in case of a dispute.
Wording the reason in case of high temperatures
Decree No. 2025-482 of May 27, 2025, requires assessing risks related to heat and considering preventive measures, including adjusting hours and rest times. This decree does not set a general maximum temperature beyond which work would be automatically prohibited.
The memo must therefore mention the employer’s safety obligation (Article L 4121-1 of the Labor Code) and specify that the adjustment of hours constitutes a preventive measure adapted to actual conditions. Simply writing “due to the heat” is not sufficient: the reason must be anchored in the regulatory framework.
Adaptable memo template for a change of hours
The template below covers the most common case: a temporary change of collective hours for full-time employees. It is not suitable for contractual modifications that require a signed amendment from the employee.
Typical document structure
Header: company name, address, SIRET number. Mention “Memo” as the title of the document, followed by the internal reference number if the company uses one.
Body: “As of [date], the working hours of the staff of [department/establishment] are modified as follows: [table of hours by day]. This modification is motivated by [specific reason]. The weekly working hours remain unchanged at [hourly volume]. These provisions apply until [end date] / until further notice.”
Closure: brief salutation, signature of the responsible person with mention of their title, date, and place.
Common mistakes to avoid in drafting
- Using an imperative tone without recalling the legal framework, which gives the impression of an unfounded unilateral decision.
- Omitting the mention of maintaining the weekly hourly volume, leaving doubt about a modification of the working duration.
- Sending the memo without respecting the notice period provided by the collective agreement, which can render it unenforceable.
- Applying the same model to part-time employees without checking if their contract includes a clause for modifying hours.
Distribution and proof of receipt of the memo
The memo is only valid if the employer can prove that the employee has been informed. Posting in the premises remains the historical method, but it does not constitute individual proof of receipt.
Hand delivery against signature offers the strongest traceability. Sending by email with electronic acknowledgment of receipt is an accepted alternative, provided that the address used is the one communicated by the employee in a professional context.
For teams on site or traveling, combining on-site posting and individual email sending covers both dimensions: collective information and personalized proof. The choice of distribution channel should be mentioned in the memo itself, which most online templates do not provide.
Drafting a memo for changing hours relies less on formality and more on the correct legal qualification of the change. A well-constructed template first identifies the nature of the modification before choosing its wording and retains proof of its distribution.
