The employer who finds that the employee has abandoned his post and intends to invoke the presumption of resignation provided for in article L. 1237-1-1 shall give him formal notice, by registered letter or by letter delivered personally against receipt, to justify his absence and to return to his post.
In the event that the employee intends to invoke a legitimate reason from the employer such as to preclude a presumption of resignation, such as, in particular, medical reasons, the exercise of the right of withdrawal provided for in article L. 4131-1, the exercise of the right to strike provided for in Article L. 2511-1, the employee’s refusal to carry out an instruction contrary to a regulation or the modification of the employment contract at the employer’s initiative, the employee shall indicate the reason he invokes in the reply to the aforementioned formal notice.
The period mentioned in the first paragraph of Article L. 1237-1-1 may not be less than fifteen days. This period begins to run from the date of presentation of the formal notice provided for in the first paragraph.