Where the number of employees employed by the debtor, determined in accordance with the provisions of 4° of Article R. 621-1, is at least equal to 50, the guarantee institutions mentioned in Article L. 3253-14 of the Labour Code are invited by the Registrar to make known the person authorised to represent them at the hearing. The observations provided for in the fifth paragraph of article L. 621-4 may also be collected in writing; they shall then be communicated to the debtor and the Public Prosecutor by the court clerk’s office.