Small reminder from the Social Chamber: overtime worked by an employee cannot be compensated by the payment of bonuses but must give rise to the payment of increased remuneration (or compensatory time off also increased, if applicable).
Be careful, trying to replace the payment of overtime with bonuses may require you to pay twice.
This practice, if it hurts the employee as to the amount paid, also deprives him of the allocation of any compulsory compensation on rest (if the annual quota of overtime is exceeded) but also of tax and social exemptions attached to the payment of overtime.
In short, this is clearly not a good calculation.
Patchwork Avocats can help you see more clearly in terms of working hours and set up a adapted organization aimed at limiting the payment of overtime.