Overtime: Salary Increase and Calculation under Law

Introduction

Overtime constitutes a central issue in French labour law. Whether an employee wishes to understand their payslip or an employer seeks to comply with their legal obligations, the calculation of overtime and applicable increase rates 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 trigger threshold, minimum increase rates and the modalities for replacement by compensatory rest. This article offers you a complete and factual guide to master these mechanisms, avoid employment tribunal disputes and optimise the administrative management of your human resources.

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What is an hour of overtime?

Legal definition and trigger threshold

An hour of overtime is any hour of work performed beyond the statutory weekly duration of 35 hours set by article L. 3121-27 of the Labour Code. This threshold is assessed on the scale of the civil week (Monday 0:00 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 the 35 weekly hours are supplementary hours, subject to a distinct regime. They do not fall within the overtime scheme, but nonetheless 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 statutory contingent of overtime hours is set at 220 hours per year and per employee (art. D. 3121-24), unless a company or industry-wide collective agreement modifies it upwards or downwards. 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 obligation (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 the management of employment contracts and their compliant electronic signature, particularly when modulation amendment deeds must be drawn up quickly.

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The statutory increase rates for overtime

Minimum increase provided by law

The Labour Code provides minimum increase rates that apply in the absence of more favourable collective agreements:

| Tranches of overtime hours | Minimum increase rate | |---|---| | 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, reimbursement of expenses or profit-sharing distributions are generally excluded from the calculation base.

Role of collective agreements

A company or industry-wide agreement may modify these rates downwards 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 metallurgical sector (IDCC 3127), construction or retail trade frequently provide for specific provisions.

Replacement of the increase by compensatory rest for replacement

The employer may, with the employee's agreement or by collective agreement, substitute all or part of the salary increase with a compensatory rest for 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. Rest must be taken within a maximum period of 12 months.

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How to concretely calculate overtime?

Formula for calculating the increased hourly rate

The calculation is based on the following formula:

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

That is, for an employee paid EUR 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 statutory monthly duration (35 h × 52 weeks / 12 months).

Practical case: 42-hour week

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

• 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 Act of 2007 and its successive updates, overtime hours have benefited from a favourable exemption scheme:

• Income tax exemption within the limit of €7,500 per year (limit applicable in 2026, art. 81 quater of the Tax Code) ;

• Reduction of employee contributions of 11.31 points on basic and supplementary pension contributions (decree no. 2019-797) ;

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

These benefits make overtime particularly attractive for employees, with a net gain often greater than an ordinary taxable bonus. For HR services, the dematerialisation of payslips via a compliant solution considerably facilitates the traceability of these variable elements.

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Employer obligations and risks in case of non-compliance

Keeping the working time register

The employer is legally required to account for the effective working time of each employee (art. L. 3171-2 and R. 3243-1). This accounting can take the form of a time-tracking system, time and attendance management software (GTA) or a weekly hourly statement signed. This document constitutes proof in case of employment 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 time-tracking system, it is up to the employer to prove the schedules actually worked — not the employee. The stakes are considerable: the burden of proof reverses.

Sanctions in case of non-payment

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

• Back pay with statutory interest before the Employment Tribunal;

• Damages for disloyal performance of the employment contract;

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

• Social security audit with application of late payment surcharges.

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

Absolute maximum working hours to be observed

Even in the presence of overtime, the employer cannot exceed absolute statutory limits:

• 10 hours per day (except prefectural exemption or collective agreement);

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

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

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

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Administrative management and dematerialisation of documents related to overtime

Contract amendments and required formality

Certain modifications to working time (transition to a day-based salary agreement, annual modulation, recurring recourse to 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 that it guarantees the identity of the signatory and the integrity of the document.

The electronic signature for human resources meets precisely this need: signing amendments remotely, qualified time-stamping, preservation of proof of signature for the entire statutory prescription period (5 years in payroll matters).

Dematerialised payslips and traceability of variable elements

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

The use of a electronic signature solution integrated into the HRIS makes it possible to centralise the validation of hour records, payslips and amendments in a single, auditable environment at any time by the labour inspectorate or in case of employment tribunal proceedings.

Legal framework applicable to overtime

Reference texts of 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:

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

• Default 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 Tax Code

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

Reductions in social contributions

The reduction of employee 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 reduction rate is currently 11.31 points for employees under the general scheme. The EUR 1.50 per hour employer forfeiture deduction 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". Article 1367 of the Civil Code clarifies that 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 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 overtime hour records and modulation amendments, advanced or qualified electronic signature is recommended to ensure their enforceability in case of dispute. The ETSI EN 319 132 standard defines XAdES/PAdES formats accepted for long-term probative value (LTV) signatures.

Risks regarding concealed work

Article L. 8221-5 of the Labour Code qualifies as concealed work the fact of intentionally mentioning on the payslip a number of hours lower than that actually worked. Criminal sanctions reach 3 years' imprisonment and EUR 45,000 fine for natural persons, increased to EUR 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 mode of management.

Usage scenarios: managing overtime with electronic signature

Scenario 1 — Industrial SME with strong seasonality

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

Before dematerialisation, the process involved printing, handwritten signature, scanning and physical archiving — approximately 45 minutes per file for the HR service. 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 preserved for the entire statutory prescription period.

Scenario 2 — Accounting firm managing payroll for 150 micro and small-medium enterprises

An accounting firm specialising in payroll management handles remuneration for 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 an hour record by the employer before payroll is established.

Thanks to the integration of an electronic signature workflow, managers of client companies validate their hour 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 man-days per month on follow-up and collection of validations, allowing it to reassign these resources to higher value-added assignments.

Scenario 3 — Distribution group with multi-site employees

A food retail distribution group operating around twenty sales points 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 overruns, requests for compensatory rest and ad hoc amendments for last-minute replacements.

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

Conclusion

Overtime is subject to a precise legal framework that every employer must master: trigger threshold at 35 hours, increase rates of 25% then 50%, annual contingent of 220 hours, tax and social exemptions capped at EUR 7,500 per year. Non-compliance with these rules exposes employers to significant employment tribunal and criminal risks, whilst good management of these variable elements strengthens team confidence and payroll reliability.

The dematerialisation of associated documents — amendments, hour records, payslips — is today an unavoidable 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.