Any declaration or communication emanating from the employee or the employer shall be made by registered letter with acknowledgement of receipt or by any other means which provides proof that it has been received by the other party.
The declaration provided for in Article R. 611-1 may result from the transmission by the National Institute of Industrial Property to the employer, in accordance with the procedures laid down by order of the Minister responsible for industrial property, of the second copy of an envelope sent by the employee to the Institute to be kept there.
This procedure is optional for the interventions referred to in the first paragraph of Article L. 611-7.