Overtime must be paid at the end of the month by the employer. What are the appeals of the employee in case of non-payment?
It may be a simple oversight. In this case, to announce the error to the employer should be enough to rectify the situation.
However, the employer refuses sometimes to pay the overtime, either because the company lacks money, either because he disputes the reality of overtime. If you are in this situation, you must send a mail recommended with acknowledgement of receipt to your employer.
In your letter, you mention him the hours of overtime worked and require payment. If you can, attach to this letter from the evidence as to the e-mail asking you to work overtime, pointed out time clock, professional emails during overtime, testimonials written of colleagues, etc.
If despite your written request your employer refuses to comply with your request, you can turn to the delegated staff, a trade union or labor inspector. These different stakeholders can help you in your approach through the means at their disposal: mediation, pressure, sanctions, etc.
If the efforts of conciliation in unpaid overtime have not allowed you to achieve a satisfactory result, you will have to turn to justice. The Labor Tribunal is the competent court for disputes based on the contract of employment. You can enter without a lawyer, even if the advices of a legal professional are important.
Be sure to constitute a file proving the reality of overtime and their non-payment. Ask your colleagues to collect evidence. You can then go to the arbitration court to defend your rights, on conciliation and trial phases. If you succeed, you can not only claim the settlement of unpaid overtime, but also an allowance you compensating for the prejudice suffered.