Overtime: Salary Increase and Calculation According to the Law

Introduction

Overtime is a central issue in French labor 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 increase rates regularly raise complex questions. In 2026, the legal framework arising from the Labor Code (articles L. 3121-28 to L. 3121-40) precisely defines the trigger threshold, the minimum increase rates and the methods of replacement by compensatory rest. This article provides you with a complete and factual guide to master these mechanisms, avoid labor court disputes and optimize the administrative management of your human resources.

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What is an overtime hour?

Legal definition and trigger 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 Labor Code. This threshold is assessed on a weekly scale (Monday 0:00 to Sunday 24:00), unless a collective agreement provides otherwise by organizing working time over a multi-week cycle.

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

Annual contingent of overtime hours

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

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

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

These thresholds are important to master for management of employment contracts and their compliant electronic signature, particularly when modification agreements must be established quickly.

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Legal increase rates for overtime hours

Minimum increase provided by law

The Labor Code provides for minimum increase rates that apply in the absence of a more favorable collective agreement:

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

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

Role of collective agreements

A company or industry agreement may modify these rates downward to a minimum of 10% (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 company agreements in force. Collective agreements in the metallurgy (IDCC 3127), construction or retail trade sectors frequently provide for specific provisions.

Replacement of the increase by compensatory rest

The employer may, with the agreement of the employee or by collective agreement, substitute all or part of the salary increase with a compensatory rest replacement (COR). 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 = Monthly gross base 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 hours × 52 weeks / 12 months).

Practical case: 42-hour week

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

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

• Additional gross amount: 7 × 17.30 = 121.10 €

Tax and social exemption of overtime hours in 2026

Since the TEPA law of 2007 and its successive updates, overtime hours benefit from a favorable exemption regime:

• Exemption from income tax up to 7,500 € per year (threshold applicable in 2026, art. 81 quater of the General Tax Code);

• Reduction in employee social contributions of 11.31 percentage points on basic and supplementary pension contributions (decree n° 2019-797);

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

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

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Employer obligations and risks in case of non-compliance

Maintenance of the work time register

The employer is legally required to measure the actual working time of each employee (art. L. 3171-2 and R. 3243-1). This measurement may take the form of a clocking system, time management software (GTA) or a weekly hourly statement signed. This document constitutes evidence in the event of labor court litigation.

The Court of Cassation reminded us in its ruling of November 18, 2020 (n° 18-10.919) that in the absence of a reliable measurement system, it is the employer's responsibility to prove the hours actually worked — not the employee's. The issue is considerable: the burden of proof is reversed.

Penalties for non-payment

Non-payment of overtime hours exposes the employer to several risks:

• Salary reimbursement with legal interest before the Labor Court;

• Damages for disloyal performance of the employment contract;

• Undeclared work if the default is intentional (art. L. 8221-5), punishable by a fine of 45,000 € and 3 years imprisonment for individuals;

• URSSAF audit with application of late payment penalties.

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

Absolute maximum working periods to respect

Even with overtime hours, the employer cannot exceed the absolute legal ceilings:

• 10 hours per day (except by prefectural exemption 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 organizes the annualization of working time. Special care is required particularly in highly seasonal sectors (tourism, construction, logistics).

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Administrative management and digitalization of documents related to overtime hours

Contractual amendments and required formalities

Certain changes in working time (shift to a days-based forfeit agreement, 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 recognizes the legal value of the electronic signature, provided it guarantees the identity of the signatory and the integrity of the document.

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

Digitalized payslips and traceability of variable elements

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

The use of an electronic signature solution integrated into the HRIS makes it possible to centralize the validation of time records, payslips and amendments in a single, auditable environment at any time by the labor inspectorate or in the event of labor court proceedings.

Legal framework applicable to overtime hours

Reference texts of the Labor Code

The overtime regime is governed by articles L. 3121-27 to L. 3121-40 and D. 3121-24 of the Labor Code, derived from the Labor Law of August 8, 2016 (law n° 2016-1088) and its implementing ordinances. These provisions distinguish:

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

• Supplementary rules applicable in the absence of a collective agreement (increase rates of 25% and 50%, contingent of 220 hours);

• The field open to collective bargaining.

Tax regime: article 81 quater of the General Tax Code

The exemption from income tax on overtime hours is codified in article 81 quater of the General Tax Code, modified by the Finance Law for 2019 (law n° 2018-1317). The exemption ceiling is 7,500 € per year in 2026. This provision applies only to hours legally qualified as overtime (beyond 35 weekly hours 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 n° 2019-797 of July 26, 2019. The reduction rate is currently 11.31 percentage points for employees subject to the general regime. 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 recognizes that "electronic writing has the same probative force as writing on paper support". Article 1367 of the Civil Code specifies that the electronic signature is reliable as soon as it makes it possible to identify the signatory and guarantees the integrity of the document.

The eIDAS regulation n° 910/2014 of the European Parliament and Council of July 23, 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 overtime hour records and modulation amendments, advanced or qualified electronic signature is recommended to guarantee their opposability in case of dispute. The standard ETSI EN 319 132 defines the accepted formats XAdES/PAdES for signatures with long-term probative value (LTV).

Risks regarding undeclared work

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

Usage scenarios: managing overtime hours with electronic signature

Scenario 1 — Industrial SME with strong seasonality

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

Before digitalization, the process involved printing, handwritten signature, scanning and physical filing — about 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% in administrative processing time. Amendments are signed remotely by operators from their phones, and traceability is automatically preserved throughout the legal period of limitation.

Scenario 2 — Accounting firm managing payroll for 150 SMEs

An accounting firm specializing in payroll management handles the remuneration of approximately 150 client companies, representing 2,000 monthly payslips including variable elements (overtime, bonuses, COR). Each month, a significant proportion of these payslips requires validation of a time record by the employer before payroll is established.

Thanks to the integration of an electronic signature workflow, client company managers validate their 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 collection of validations, allowing the reallocation of these resources to higher value-added assignments.

Scenario 3 — Distribution group with multi-site employees

A food distribution group operating about twenty stores in the region employs approximately 400 employees, mostly working part-time with variable supplementary and overtime hours each week. The HR department must manage in real-time the exceedances of contingent, requests for compensatory rest and occasional 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 trigger threshold is reached. The signing delay went from 5 business days to less than 4 hours on average. This responsiveness made it possible to reduce by 65% labor court 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: 35-hour trigger threshold, 25% then 50% increase rates, 220-hour annual contingent, tax and social exemptions capped at 7,500 € per year. Non-compliance with these rules exposes the company to significant labor court and criminal risks, while proper management of these variable elements strengthens team confidence and payroll reliability.

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

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