The procedure referred to in Article L. 121-7 of the Labour Code must be complied with by the employer only if the following two conditions are met:
- the planned change is detrimental to the employee; and
- the change affects a substantial clause of the employment contract.
If the employer has serious grounds to justify a change to the contract to the detriment of the employee, he must follow the same procedure as in the case of dismissal with immediate effect.
The employer must notify the employee of the changes by registered letter, precisely setting out the serious ground justifying such modifications.
If the employer is obliged to hold a pre-dismissal interview, a change with immediate effect must be notified no earlier than the day following the day of the pre-dismissal interview and no later than 8 days after that interview (unless the applicable collective work agreement lays down other time-limits).
It is to be noted that, by contrast with the dismissal procedure, failure to comply with the formality of a prior interview gives rise not only to "a formal irregularity" but also to the nullity of the change to the contract.