Overtime Hours: Salary Increase and Calculation According to Law

Introduction

Overtime hours constitute a central issue in French labour law. Whether it is an employee wishing to understand their payslip or an employer seeking to comply with their legal obligations, the calculation of overtime hours and the applicable rate increases regularly raise complex questions. In 2026, the legal framework stemming from the Labour Code (articles L. 3121-28 to L. 3121-40) precisely defines the triggering threshold, minimum rate increases and the terms for replacement by compensatory rest. This article offers you a complete and factual guide to master these mechanisms, avoid industrial tribunal disputes and optimise the administrative management of your human resources.

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What is an overtime hour?

Legal definition and triggering threshold

An overtime hour is any hour of work performed beyond the legal weekly duration of 35 hours set by article L. 3121-27 of the Labour Code. This threshold is assessed on a calendar week scale (Monday 00:00 to Sunday 24:00), unless a collective agreement provides otherwise by organising working time over a multi-week cycle.

For part-time employees, hours worked beyond the contract but below 35 hours per week are supplementary hours, subject to a separate regime. They do not fall under the overtime scheme, but nevertheless benefit from a specific increase as soon as they exceed 1/10th of the contractual duration (art. L. 3123-20).

The annual contingent of overtime hours

The legal contingent of overtime hours is set at 220 hours per year and per employee (art. D. 3121-24), unless a company or sectoral collective agreement modifies it upwards or downwards. Beyond this contingent:

• The employer must obtain the opinion of the social and economic committee (SEC) before resorting to hours outside the contingent;

• The employee benefits from a mandatory compensatory rest (COR) of 50% for companies with 20 employees or fewer, and 100% for companies with more than 20 employees (art. L. 3121-38).

These thresholds are important to master for managing employment contracts and their conforming electronic signature, in particular when modulation amendments must be established quickly.

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The legal rate increases for overtime hours

Minimum increase provided by law

The Labour Code provides for minimum rate increases that apply in the absence of a more favourable collective agreement:

| Tranches of overtime hours | Minimum rate increase | |---|---| | 1st to 8th overtime hour (H36 to H43) | 25% | | From the 9th overtime hour (H44 and beyond) | 50% |

These rates are calculated on the gross hourly basic remuneration, including salary elements integrated into this base (seniority bonus integrated into the hourly rate, for example). Conversely, exceptional bonuses, expense reimbursements or profit sharing are generally excluded from the calculation base.

Role of collective agreements

A company or sectoral agreement may modify these rates downwards to a 10% minimum (art. L. 3121-33), or increase them beyond 50%. Before proceeding with the calculation, it is therefore essential to check the applicable collective agreement (IDCC) and any collective company agreements in force. Collective agreements in the metallurgy (IDCC 3127), construction or retail trade sectors frequently provide specific provisions.

Replacement of the increase by compensatory rest

The employer may, with the employee's agreement or by collective agreement, replace all or part of the salary increase with a compensatory rest replacement (RCR). This mechanism, provided for in article L. 3121-33, is tax-neutral for the employee but allows the employer to reduce the immediate payroll. The rest must be taken within a maximum period of 12 months.

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How to concretely calculate overtime hours?

Formula for calculating the increased hourly rate

The calculation is based on the following formula:

Gross hourly rate = Gross monthly basic salary ÷ (35 × 52 / 12)

For an employee paid €2,100 gross per month:

• Hourly rate = 2,100 ÷ 151.67 = €13.84 gross/hour

• 25% increase: 13.84 × 1.25 = €17.30 gross/hour

• 50% increase: 13.84 × 1.50 = €20.76 gross/hour

The divisor 151.67 corresponds to the legal monthly duration (35 h × 52 weeks / 12 months).

Practical case: week with 42 hours

If an employee works 42 hours in the week (i.e. 7 overtime hours):

• Hours 36 to 43: the first 7 overtime hours are increased by 25%

• Gross additional amount: 7 × 17.30 = €121.10

Tax and social exemption for overtime hours in 2026

Since the TEPA Act of 2007 and its subsequent updates, overtime hours benefit from a favourable exemption scheme:

• Exemption from income tax within the limit of €7,500 per year (ceiling applicable in 2026, art. 81 quater of the CGI);

• Reduction in employee social contributions of 11.31 points on basic and supplementary pension contributions (Decree No. 2019-797);

• Employer tax deduction of €1.50 per overtime hour for companies with fewer than 20 employees.

These advantages make overtime hours particularly attractive for employees, with a net gain often exceeding an ordinary taxable bonus. For HR departments, digitisation of payslips via a compliant solution greatly facilitates the traceability of these variable items.

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Employer obligations and risks in case of non-compliance

Keeping a working time register

The employer is legally required to record the actual working time of each employee (art. L. 3171-2 and R. 3243-1). This record can take the form of a time-tracking system, workforce management software (GTA) or a weekly hours statement signed. This document is evidence in case of industrial tribunal dispute.

The Court of Cassation recalled in its ruling of 18 November 2020 (No. 18-10.919) that in the absence of a reliable record system, it is the employer who must prove the hours actually worked — not the employee. The issue is significant: the burden of proof is reversed.

Sanctions in case of non-payment

Failure to pay overtime exposes the employer to several risks:

• Back-payment of salary with legal interest before the Industrial Tribunal;

• Damages and interest for breach of the employment contract;

• Undeclared work if the failure is intentional (art. L. 8221-5), subject to a fine of €45,000 and 3 years' imprisonment for natural persons;

• Social security redressment with application of late-payment penalties.

To secure these processes and produce irrefutable evidence in case of disputes, many HR departments now rely on qualified electronic signature compliant with eIDAS to validate working time records and contractual amendments.

Absolute maximum working durations to be respected

Even in the presence of overtime, the employer cannot exceed the absolute legal ceilings:

• 10 hours per day (unless a prefectural waiver or collective agreement);

• 48 hours per week (absolute maximum duration, art. L. 3121-20);

• 44 hours on average over any 12-week consecutive period (art. L. 3121-22).

These limits apply even when a collective agreement organises annualised working time. Vigilance is essential, particularly in sectors with high seasonality (tourism, construction, logistics).

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Administrative management and digitisation of documents related to overtime hours

Contractual amendments and required formalities

Certain changes in working time (transition to a day-based forfeit convention, annual modulation, recurring use of overtime beyond the contingent) require an amendment to the employment contract, which must be signed by both parties to be enforceable. Article 1366 of the Civil Code fully recognises the legal value of electronic signature, provided it guarantees the signer's identity and the integrity of the document.

Electronic signature for human resources precisely meets this need: signing of amendments remotely, qualified time-stamping, retention of signature proofs for the entire legal limitation period (5 years in employment law matters).

Digitised payslips and traceability of variable items

Since the Decree of 16 December 2016, the employer may issue the payslip in electronic form without prior employee consent (art. L. 3243-2), provided it guarantees its integrity and accessibility. Overtime hours, their number and their rate increase must appear distinctly (art. R. 3243-1, 15°).

Using an electronic signature solution integrated into the HRMS makes it possible to centralise the validation of working time records, payslips and amendments in a single, auditable environment at any time by the labour inspectorate or in the event of industrial tribunal proceedings.

Legal framework applicable to overtime hours

Reference texts from the Labour Code

The overtime regime is governed by articles L. 3121-27 to L. 3121-40 and D. 3121-24 of the Labour Code, stemming from the Labour Act of 8 August 2016 (Act No. 2016-1088) and its implementing ordinances. These provisions distinguish:

• Absolute public policy rules (maximum durations, 10% floor rate in case of derogatory agreement);

• Default rules applicable in the absence of a collective agreement (25% and 50% rate increases, 220-hour contingent);

• The scope open for collective bargaining.

Tax regime: article 81 quater of the CGI

The exemption from income tax on overtime hours is codified in article 81 quater of the General Tax Code, amended by the Finance Act for 2019 (Act No. 2018-1317). The exemption ceiling is €7,500 per year in 2026. This provision applies only to hours legally qualified as overtime (beyond 35 hours per week or the conventional ceiling).

Reductions in social contributions

The reduction in employee social contributions is defined by article L. 241-17 of the Social Security Code and clarified by Decree No. 2019-797 of 26 July 2019. The current reduction rate is 11.31 points for employees under the general scheme. The employer tax deduction of €1.50 per hour is reserved for companies with fewer than 20 employees (art. L. 241-18 CSS).

Legal value of electronic signature on HR documents

Amendments relating to working time arrangements are legal acts within the meaning of article 1366 of the Civil Code, which recognises that "electronic writing has the same probative force as writing on paper support". Article 1367 of the Civil Code clarifies that electronic signature is reliable as soon as it allows the signer to be identified and guarantees the integrity of the document.

The eIDAS Regulation No. 910/2014 of the European Parliament and of the Council of 23 July 2014 establishes three levels of electronic signature:

• Simple: for documents with low stakes;

• Advanced: for ordinary contracts and amendments;

• Qualified: only level legally equivalent to handwritten signature throughout the EU.

For working time records of overtime hours and modulation amendments, advanced or qualified electronic signature is recommended to guarantee their enforceability in case of dispute. The ETSI EN 319 132 standard defines XAdES/PAdES formats accepted for long-term value (LTV) signatures.

Risks in terms of undeclared work

Article L. 8221-5 of the Labour Code qualifies as undeclared work the intentional statement on the payslip of a number of hours lower than that actually worked. Criminal penalties reach 3 years' imprisonment and a €45,000 fine for natural persons, increased to €225,000 for legal persons (art. L. 8224-1 and L. 8224-5). The case law of the Court of Cassation also condemns the systematic recourse to unpaid overtime as an ordinary management method.

Usage scenarios: managing overtime hours with electronic signature

Scenario 1 — Industrial SME with high seasonality

An SME in the mechanical manufacturing sector, with approximately 80 employees, experiences recurring peaks in activity from April to September. Each year, its production teams work an average of 15 to 18 hours of overtime per employee during high-load weeks, requiring the drafting of several dozen annual modulation amendments and weekly working time records countersigned.

Before digitisation, the process involved printing, handwritten signature, scanning and physical filing — approximately 45 minutes per file for the HR department. By deploying an advanced electronic signature solution compliant with eIDAS for these documents, the company reduced this time to less than 8 minutes per file, a reduction of 82% of administrative processing time. Amendments are signed remotely by operators from their mobile phone, and traceability is automatically retained for the entire legal limitation period.

Scenario 2 — Accounting firm managing payroll for 150 SMEs

An accounting firm specialising in payroll management provides payroll services for approximately 150 client companies, representing 2,000 monthly payslips including variable items (overtime, bonuses, COR). Each month, a significant proportion of these payslips require validation of a working time record by the employer before payroll is established.

Through integration of an electronic signature workflow, company managers validate their working time records online in less than 2 minutes, compared to 24 to 48 hours previously via email or mail exchanges. The firm estimated a saving of 3 person-days per month on follow-up and validation collection, allowing these resources to be redirected to higher value-added assignments.

Scenario 3 — Retail group with multi-site employees

A food distribution group operating twenty retail outlets in the region employs approximately 400 employees, most of whom work part-time with variable supplementary and overtime hours each week. The HR department must manage in real-time contingent exceedances, requests for compensatory rest and one-off amendments for last-minute replacements.

By connecting its GTA software to an electronic signature API, the group automates the generation and signing of weekly amendments as soon as a triggering threshold is reached. The signing time has fallen from 5 working days to less than 4 hours on average. This responsiveness has made it possible to reduce by 65% industrial tribunal disputes related to unsigned or late-signed amendments, according to the internal analysis of the legal department over 18 months.

Conclusion

Overtime hours are subject to a precise legal framework that every employer must master: triggering threshold at 35 hours, rate increases of 25% then 50%, annual contingent of 220 hours, tax and social exemptions capped at €7,500 per year. Non-compliance with these rules exposes you to significant industrial tribunal and criminal risks, whilst good management of these variable items strengthens team confidence and payroll reliability.

The digitisation of associated documents — amendments, working time records, payslips — is now an essential HR efficiency lever. Certyneo offers you an electronic signature solution compliant with eIDAS, specifically adapted to the needs of HR and legal teams.

Ready to secure and accelerate your document processes? Discover our pricing and start free on Certyneo today.